No modifications! Simple to install! Using the ESWKIT to convert your Large Post bridge system couldn’t be easier! Simply unscrew the original integrated bridge post/thumbwheel and replace with the ESWKIT. You are now ready to install your Tone-Lock™ bridge and the rest of the parts in your Master Kit in no time! Gives your guitar more pleasing tone by using the best German steel, as opposed to the original Zamac (zinc alloy) bridge posts you will be replacing.