PRO-4 Ball End - Series 192 Series 192 Vibration Reducing End Mill with Ball End. The patented PRO-4 by PROMAX. View Speeds and Feeds page. Features: Eliminates Chatter & Vibration Delivers and Excellent Finish Relieves cutting pressure against the tools with OD Chip Breakers Easy & Inexpensive to Regrind Standard with Advanced AlTiN Coating (Part Number Ending in 4) Standard with nACRo® Coating (Part Number Ending in 5)