Tired of trying to secure your AR parts while installing a pin detent or spring Specifically designed for AR15 assembly and disassembly the AR15 Bench Block is the perfect tool. Made of extremely durable nonmarring urethane to protect the finish of your firearms and last for years. It features a variety of notches grooves and holes on both sides and is ideally suited for the upper receiver lower receiver front sight and charging handle of an AR15.