One piece 40% glass filled nylon design, light weight carbon fiber side plates, built in anchor point for a bungee line with a 2.5 mm reel line guide, along with an easy and fast loading system. The new ceramic bearings are smooth and low friction for maximum power transfer and ease in loading. The encapsulated ceramic balls stop sand and saltwater damage and are virtually maintanence free and come with a lifetime warranty. By eliminating recoil and generating more than double the power for a given barrel length, a roller power head offers greater accuracy, penetration, range and manueverability. Utilizes 100% of the barrel length to propel the spear. Along with properly pretensioned rubbers and a greater rubber stretch to spear weight ratio yielding significantly more power. Any Euro/South African speargun with a cylindrical removable muzzle can be converted into a roller speargun with this system. The kit is available in your choice of black, white, or red muzzle and bearing colors. 16 mm small ID reactive rubber, one adapter, 3 different types of dyneema lines for installation, stainless fittings and easy to follow, indepth rigging instructions. 2 wraps of shooting line is recommended. Best suited for spearguns ranging in size from 80 to 120 cm in length. Select the appropriate adapter size by measuring the barrel inner diameter.