Dremel Precision Drill Bit Set - 7 Piece Shells harden with age, so newer shells will be easier to drill than ones that have been in your collection a while. You may need to adjust the speed of the dremel rotary tool when drilling shell, but you should always advance the drill bit into the shell slowly (slow feed rate). Gradual drilling will extend the life of the drill bit. Diamond point 7134 requires a 481 collect. Features: - Usage: Includes 7 precision drill bits 0.8mm - 3.2mm - Maximum RPM: 35.000 1/min