Refine Durable Plastic Pen

I already have a near-finished pen concept modelled in CAD; what I need now is a fresh set of expert eyes to make sure the entire piece is truly production-ready. We will walk through the current files... (Budget: $10 - $30 USD, Jobs: 3D CAD, 3D Modelling, 3D Rendering, CAD/CAM, Engineering Drawing, Manufacturing, Product Development, Solidworks)