JIS Plain Linear Bearing FJ13 13mm Closed, Precision ID Crowned outer diameter (OD) is

Crowned outer diameter (OD) is self-aligning

Anodized aluminum shell colored green

Double Plain Linear Bearing of 8mm JIS Metric ID with an end-mounted square flange and a compensated running clearance of 0

durable green anodized aluminum shell

JIS Plain Linear Bearing FJ13 13mm Closed, Precision ID Crowned outer diameter (OD) isClosed shell plain linear bearing with a JIS 13mm ID, precision running clearance, durable green anodized aluminum shell, and a bonded self lubricating FrelonGOLD liner that facilitates smooth linear, rotational, or oscillating motion on round shafts in harsh conditions where contamination, vibration, shock loads, washdowns, temperature extremes, lubricant maintenance difficulties, or poor machine accessibility can make rolling element bearings harder