Long Case Clock Pendulum Flat and Hexagonal Nut

•Mainspring let down tools are used to safely unwind your clock’s powerful mainspring, so that you may disassemble the movement for proper cleaning and lubrication without injuring yourself and causing extensive damage to the movement. •These tools are designed to fit over your clock’s key, and work for almost all keys currently on the market. •Durable plastic handle with chucks made from quality steel.

Key sizes: 5-6, 7-8 and 10-12. Put chuck in the handle and slowly release the mainspring.