D'Addario PW-LBK-01 LUBRIKIT Guitar String Friction Remover Kit:
The D'Addario LubriKit is an easy-to-use lubricant for friction points, including the nut and string saddles for all string instruments. Friction is the root cause of many tuning problems. Just a drop of LubriKit removes the friction so you can play in tune. The easy-to-use formula comes in a syringe style applicator along with 2 swabs for getting into tight spaces. Just a drop in each nut slot and string saddle allows the strings to glide effortlessly, preventing friction that can cause strings to bind and go out of tune. LubriKit can also be used for all contact points with floating bridges and string height adjustment screws.