This R315E is a medium, metricseries Cylindrical Roller Bearing with two lips on the outer race and a standard internal clearance. The bearing's dimensions are 15x42x13mm

This R315L is a medium, metricseries Cylindrical Roller Bearing with one lip on the outer race, two lips on the inner race and a standard internal clearance. The bearing's dimensions are 15x42x13mm

This R315P is a medium, metricseries Cylindrical Roller Bearing with two lips on the outer race, one lip on the inner race and a standard internal clearance. The bearing's dimensions are 15x42x13mm