Koji "No. 63" of Laylax talks about the made to order Proto Gear Arts P90 Stealth Upper Receiver which is compatible with the Tokyo Marui P90 series. It might fit with the Marui P90 clones, so better check first. This is a 3D printed lightweight upper receiver, reminiscent of the popular "XF50 Tri-Rail". It features an optimal height top rail for easy sighting, side rails at barrel height for effective use of flashlights and laser sights, and a guide slider in the magazine section to aid reloading. The receiver is made from lightweight, rigid nylon resin. Two models are available: the "Picatinny Rail Type", which includes three Picatinny rails and a live charging handle, weighing around 270g; and the "M-LOK type", a lighter model with two M-LOK slots on each side and no charging handle, weighing approximately 230g. Both models are significantly lighter than Tokyo Marui's genuine upper receiver for P90+.