diff --git a/main.scad b/main.scad
index 3d88a6a..64d1639 100644
--- a/main.scad
+++ b/main.scad
@@ -23,16 +23,24 @@ function is_model(m) = is_not_export() || export == m;
 
 function get_phone_size() = [160, 76.7, 10];
 
+module cubi(s, fillet=0, edges=EDGES_ALL) {
+    if ($preview) {
+        cube(s, center=true);
+    } else {
+        cuboid(s, fillet=fillet, edges=edges);
+    }
+}
+
 module phone() {
     s=get_phone_size();
     color("gray")
-    cuboid(s, fillet=5);
+    cubi(s, fillet=5);
 }
 module arm() {
     $fn=6;
     s=[210, 55, 50];
     color("SaddleBrown")
-    down(s.z/2 + get_phone_size().z/2) cuboid(s, fillet=20);
+    down(s.z/2 + get_phone_size().z/2) cubi(s, fillet=20);
 }
 
 module phone_harness() {
@@ -59,8 +67,8 @@ module phone_harness() {
     module shell() {
         $fn = $preview ? 6 : 30;
         difference() {
-            cuboid(hs, fillet=f);
-            cuboid(ps, fillet=f);
+            cubi(hs, fillet=f);
+            cubi(ps, fillet=f);
         }
         shell_rim();
         shell_screwmounts();
@@ -71,10 +79,10 @@ module phone_harness() {
         s=rim_size;
         intersection() {
             difference() {
-                cuboid(s, fillet=rf, edges=EDGES_Z_ALL);
-                cuboid(ps, fillet=f, edges=EDGES_Z_ALL);
+                cubi(s, fillet=rf, edges=EDGES_Z_ALL);
+                cubi(ps, fillet=f, edges=EDGES_Z_ALL);
             }
-            cuboid(s, fillet=1);
+            cubi(s, fillet=1);
         }
         rail_extension=10;
         fwd(hs.y/2) xrot(90) harness_rail(slider_len_front+rail_extension);
@@ -88,10 +96,10 @@ module phone_harness() {
         resi=[hs.x+2*offset, hs.y+2*offset, res.z+1];
         up(0.0) difference() {
             intersection() {
-                cuboid(res, fillet=rf, edges=EDGES_Z_ALL);
-                cuboid(res, fillet=(groove?1:1.5), edges=EDGES_BOTTOM);
+                cubi(res, fillet=rf, edges=EDGES_Z_ALL);
+                cubi(res, fillet=(groove?1:1.5), edges=EDGES_BOTTOM);
             }
-            cuboid(resi, fillet=rf, edges=EDGES_Z_ALL);
+            cubi(resi, fillet=rf, edges=EDGES_Z_ALL);
         }
     }
     module foreach_screwmount() {
@@ -115,7 +123,7 @@ module phone_harness() {
         }
     }
     module shell_backplane(groove) {
-        down(hs.z/2 - shell_wall/6) up(backplane_rim_size.z/2) right(harness_divider.x) scale(groove ? 1.01 : 1) cuboid(backplane_rim_size, fillet=5, edges=EDGES_Z_LF);
+        down(hs.z/2 - shell_wall/6) up(backplane_rim_size.z/2) right(harness_divider.x) scale(groove ? 1.01 : 1) cubi(backplane_rim_size, fillet=5, edges=EDGES_Z_LF);
     }
     
     // ==== SHELL SLIDER AND RAIL ====
@@ -148,22 +156,22 @@ module phone_harness() {
     // -- TOP --
     module screen_cutout() {
         s=[138, 69, 100];
-        up(s.z/2) cuboid(s, fillet=3, edges=EDGES_Z_ALL);
+        up(s.z/2) cubi(s, fillet=3, edges=EDGES_Z_ALL);
     }
     top_offset=6.5;
     module top_speaker_cutout() {
         s=[3, 12, 100];
-        right(ps.x/2 - top_offset) up(s.z/2 - ps.z/3) cuboid(s, fillet=1);
+        right(ps.x/2 - top_offset) up(s.z/2 - ps.z/3) cubi(s, fillet=1);
     }
     module front_camera_cutout() {
         $fn = $preview ? 6 : 30;
         d=5;
         s=[d, d, 100];
-        right(ps.x/2 - top_offset) fwd(11) cylinder(d=s.x, h=s.z);
+        right(ps.x/2 - top_offset) fwd(11.5) cylinder(d=s.x, h=s.z);
     }
     module leds_cutout() {
         s=[4, 14, 100];
-        right(ps.x/2 - top_offset) up(s.z/2 - ps.z/3) back(23) cuboid(s, fillet=1);
+        right(ps.x/2 - top_offset) up(s.z/2 - ps.z/3) back(23) cubi(s, fillet=1);
     }
     module top_cutout() {
         screen_cutout();
@@ -175,13 +183,13 @@ module phone_harness() {
     // -- BOTTOM --
     module back_camera_cutout() {
         s=[13, 25, expose_back_camera ? 100 : 11];
-        right(ps.x/2 - 7.5) fwd(ps.y/2 - 23) down(s.z/2 - ps.z/3) cuboid(s, fillet=6, edges=EDGES_Z_ALL);
+        right(ps.x/2 - 7.5) fwd(ps.y/2 - 23) down(s.z/2 - ps.z/3) cubi(s, fillet=6, edges=EDGES_Z_ALL);
     }
     module bottom_speaker_cutout() {
         s=[8, 49, 100];
         left(ps.x/2 - 13)
         difference() {
-            down(s.z/2 - ps.z/3) cuboid(s, fillet=1);
+            down(s.z/2 - ps.z/3) cubi(s, fillet=1);
             bars=8;
             down(ps.z/2)
             for (i = [0:bars-1]) {
@@ -211,7 +219,7 @@ module phone_harness() {
     // -- LEFT --
     module usbc_cutout() {
         s=[100, 20, 6];
-        left(ps.x/2) down(2) cuboid(s, fillet=1);
+        left(ps.x/2) down(2) cubi(s, fillet=1);
     }
     module left_cutout() {
         usbc_cutout();
@@ -220,7 +228,7 @@ module phone_harness() {
     // -- FRONT --
     module buttons_cutout() {
         s=[42, 100, 5];
-        fwd(ps.y/2) right(ps.x/2 - 44.5) cuboid(s, fillet=1);
+        fwd(ps.y/2) right(ps.x/2 - 44.5) cubi(s, fillet=1);
     }
     module front_cutout() {
         buttons_cutout();
diff --git a/strap.scad b/strap.scad
index e05b9f9..f8cf005 100644
--- a/strap.scad
+++ b/strap.scad
@@ -13,6 +13,7 @@ use <BOSL/sliders.scad>
 MODEL_STRAP_PLATFORM_BASE=10;
 MODEL_STRAP_PLATFORM_RIB=11;
 MODEL_STRAP_PLATFORM_RIB_BRACE=12;
+MODEL_STRAP_SECONDARY=13;
 export=0; // [0:20]
 function is_not_export() = is_undef(export) || export == 0;
 function is_export() = !is_not_export();
@@ -25,20 +26,24 @@ module arm() {
     $fn=$preview ? 10 : 30;
     arm_size=[200, 55, 40];
 color("gray")
-down(arm_size.z/2) cuboid(arm_size, fillet=16, edges=EDGES_X_ALL);
+down(arm_size.z/2) {
+        cuboid(arm_size, fillet=16, edges=EDGES_X_ALL);
+        left(arm_size.x*0.6) scale([1, 1, 0.8]) yrot(90) cylinder(d1=arm_size.y*1.4, d2=arm_size.y*0.95, h=arm_size.x/2);
+    }
 }
 
 module strap_platform() {
     base_size=[40, 70, 2];
-    rib_thickness=2;
+    rib_thickness=5;
     rib_height=20;
     rib_pos=[base_size.x/2 - rib_thickness, 0, -1.3];
     brace_size=[base_size.x, 3.6, 4.8];
     brace_pos=[0, base_size.y/2 - 4, -1.3];
     module platform_base() {
+        cutout_size=[(base_size.x-rib_thickness*2 - 2*(base_size.x/2-rib_pos.x)), (base_size.y - 5), 2*base_size.z];
         difference() {
             down(base_size.z/2) cuboid(base_size, fillet=2, edges=EDGES_Z_ALL);
-            down(base_size.z/2) scale([0.75, 0.85, 2]) cuboid(base_size, fillet=2, edges=EDGES_Z_ALL);
+            down(base_size.z/2) cuboid(cutout_size, fillet=2, edges=EDGES_Z_ALL);
             model_rib_left(socket=true);
             model_rib_right(socket=true);
         }
@@ -91,12 +96,39 @@ module strap_platform() {
     }
 }
 
+module strap_secondary() {
+    size=[40, 15, 10];
+    size_base=[size.x, size.y];
+    size_top=[size.x * 0.9, size.y * 0.4];
+    cutout_size=[size.x - 10, size.y*10, size.z - 4];
+    module anchor() {
+        difference() {
+            xrot(180) rounded_prismoid(size1=size_base, size2=size_top, h=size.z, r=5);
+            down(size.z/2) cube(cutout_size, center=true);
+        }
+    }
+    anchor_pos=[60, 30, 0];
+    module anchor_front() {
+        left(anchor_pos.x) fwd(anchor_pos.y) anchor();
+    }
+    module anchor_back() {
+        left(anchor_pos.x) back(anchor_pos.y) anchor();
+    }
+    
+    if (is_model(MODEL_STRAP_SECONDARY)) anchor_front();
+    if (is_not_export()) anchor_back();
+}
+
 module model_strap_platform() {
     strap_platform();
 }
+module model_strap_secondary() {
+    strap_secondary();
+}
 module model_arm() {
     if (is_not_export()) down(3) arm();
 }
 
 model_strap_platform();
+model_strap_secondary();
 model_arm();
\ No newline at end of file