Designed as direct replacement for Ibanez, Schecter and other contemporary bass manufactures, Leo Quan's Badass TK-7815 SGT Sealed Gear 4-in-Line bass tuning machines feature a high-tolerance machined brass gear (20:1 gear ratio) for maximum accuracy and minimal slippage. A durable steel worm gear and sealed housing offer maximum longevity. And to make sure they won’t weigh down your headstock, they have a lightweight zinc housing.