For demanding users with the handle speargun MEROU / AIMRITE type, the ultimate upgrade is the mechanism BW. It has top quality construction and materials for excellent durability, reliability and longevity. Studied and designed specifically to highlight the virtues of this handle and add usability, functionality and about +6 cm arming length. The location, route, high sensitivity (even at extreme loads), the shape and the inclination angle and rotation of the trigger is the most ideal, that contribute most to demonstrative shooting shots. All components are thoroughly and evenly sculptured without spikes . The breastplate heel gives ease in arming and maintain excellent image shooting. It is easily installed in minutes without requiring specific skills and conversions, as it uses the existing pins of support, the line release and trigger lock.