Manufactured by SPI Includes 2 pistons, ring sets, wrist pins, circlips as pictured SPI pistons are engineered to provide the best possible path for combustion chamber heat transfer to the cylinder walls All SPI pistons, rings, pins, circlips are manufactured to OEM specifications All individual components are interchangeable with original parts Piston weight is compatible with original piston T-Moly series with Teflon-Molybdenum coating T-Moly series pistons reduce friction, resist seizure, improve durability Made in Taiwan Pistons are for standard bore size 73.00mm Fits 1999 Polaris 550 Trail RMK 2000 Polaris 550 Trail RMK 2001 Polaris 550 Trail RMK 2002 Polaris 550 Trail RMK 2003 Polaris 550 Trail RMK 2004 Polaris 550 Trail RMK 2005 Polaris 550 Trail RMK 2006 Polaris 550 Trail RMK 2007 Polaris 550 Trail RMK 2008 Polaris 550 Trail RMK 2009 Polaris 550 Trail RMK 2010 Polaris 550 Trail RMK