Check the listing for details. K&B .40 (new model) rc engine bearings set. Condition: New. Listed at 6.77 USD. Picture is for bearing type only Picture is for engine type only K&B .40 Front Bearing: R6N 3/8 X 7/8 X .218 (7/32) Open Bearing RCBearings brand Rear Bearing: R8N 1/2 X 1 1/8 X 1/4 Premium Bearing NOTE: Measure your front bearing to make sure it is the same as this listing before ordering! RCBearings K&B two stroke rc engine bearings offer dependable, long lasting smoothness. These have as good or better performance than what came standard in your engine at a fraction of the cost of OEM bearings! NOTE: These rc bearings are not appropriate for Heli engines. All heli engines .40ci and above should use a rear bearing with a high speed plastic retainer! Beware of other sellers that try to pass off cheap standard bearings with metallic retainers for your expensive heli engine! Support Email if you don't know which bearings you need or if you are looking for a kit we don't already have.