Adjustable Length - Switch comes with a pull chain, you can cut the desired length of the chain for installation
Disassemble the switch directly instead of cutting off the old switch circuit , pry off the upper and lower cover and pull out the wire, and then install the new switch. Just insert the thread head into the thread hole and fix it. Finally pull it down to see if it will fall
Make sure to record the position of all wires before removing the old switch