The BASS II is a precision, harmonically-tunable direct replacement bridge designed to enhance Fender Jazz and Precision Basses. The special music metal material was engineered to provide synergistic resonance mass and the most efficient sound transfer for tremendous increase in attack, sustain and clarity of notes, without changing the tone of the wood. The BASS II replaces the original bridge, and eliminates the inaccurate harmonic tuning caused by "round" shaped, and "roller" saddles of other bridges, interference of string ends contacting the bridge saddles, and unwanted side movement of strings and bridge saddles for the purest tone/sound transfer possible.*Note: It is advised that the unslotted version be slotted by a tech to achieve the proper string break-angle. In some cases, the best string-to-pole piece alignment can be achieved with the unslotted version, as it is custom slotted by your tech.