TTI Firepower PMAG Magazine Extension,- Designed to work with stock spring.- Overall weight 4.1oz.- Length, 1 1/2 inch.- Patented, proven push-pin design.- Easily attaches and detaches from the magazine.- No specialty tools, devices, or additional springs required for assembly/disassembly, simply pop off the insert at the bottom of the spring and slide on the extension.- One piece design; no small parts to keep track of.- Minimal length addition to allow usage while in a prone position.- Holds 25+1 rounds on the PMAG20.- Holds 30+1 rounds on the PMAG25.- The added weight helps the magazine drop free easier for faster reloads.- CNC machined from billet aluminum.- Hard Anodized.- Made in the USA.- Reverse compatible with GEN2 PMAGs.