They provide a clean look, while keeping unwanted grit and moisture out.
Bubs Frame Plugs are designed to fill open cable routing ports or bolt holes in your frame and fork. Problem Solvers Bubs Frame Plugs Bubs 6 x 6mm Di2 Frame Plug, Bag of 4 Protects frame or fork from internal damage and rusting Fills cable routing holes for Di2 wires in your frame or fork 6 x 6mm plug, completely fills hole (no wire slot) Rubber construction Sold as Bag of 4 Bubs 6 x 6mm Di2 Frame Plug with Hole, Bag of 4 Protects frame or fork from internal damage and rusting Fills cable routing holes for Di2 wires in your frame or fork 6 x 6mm plug, slotted hole easily slips onto electronic shifter wires Rubber construction Sold as Bag of 4 Bubs 7 x 8mm Di2 Frame Plug, Bag of 4 Protects frame or fork from internal damage and rusting Fills cable routing holes for Di2 wires in your frame or fork 7 x 8mm plug, completely fills hole (no wire slot) Rubber construction Sold as Bag of 4.