AKA CNC Metal Hopup - Short Version THE AKA brand Is behind some of the best quality products on the market thus far and now bringing you all the metal Hop Up!!! What is a hopup? A hopup is one of the very first upgrades you can do to a gel blaster. A hopup once dialled in correctly will increase the accuracy and distance of your gel blaster. Features Made from alloy for greater strength. Will increase the accuracy and distance of your gel blaster. Adjustable via a grub screw. Fit with 9.5mm size inner barrel. Outer size of the Hop Up is 16mm so make sure the inner diameter of your outer barrel is larger than that. To reach the best performance, you need to insert this Hop Up onto the barrel roughly 10mm. Thank you for choosing Tactical Edge Hobbies, Australia's largest range of Gel Blasters and accessories.