PRICE FOR ONE. 1 of 23 available. The 1/4” Mini Mini Die grinder Item APT901/BO is a compact and efficient tool designed for precision grinding tasks. With a manufacturer part number of APT901/BO, this die grinder is specifically built to provide high-quality results in a small size, making it ideal for tight spaces and intricate detailing. Whether you are a professional machinist or a hobbyist, this mini die grinder is a versatile and reliable tool to have in your workshop.