TSD Tactical AEG Model SD45 - Folding Stock. The SD45 has a TSD 30-day Warranty and is GG compatible. Standard features include: Metal Outer Barrel- Metal Gearbox- Metal Gears- and Metal Hop-up Unit. Also included are 1-300rd hi-capacity magazines. Hop-up's main function is to increase the range of the BBs travel, making for longer shots. However, not all airsoft guns have a hop-up mechanism (check the make and model of your gun). Adjust your hop up lever to make it spin more or less. The hop-up mechanism on an airsoft gun imparts backspin on the BB. An adjustable piece of rubber provides resistance on the upper part of the BB when fired, causing backspin. The backspin creates a counteraction for gravity allowing the bb to shoot farther.
