Nacra crossbar end cap. These end caps are reinforced in the middle to allow users to drill a hole if needed. Used on all Nacras with round crossbars. Pictured with hole.
Nacra front crossbar end cap with hole part #2503, rear crossbar end cap without hole part #3503 Compatible with Nacra 4.5, 450, 5.0, 5.2, 5.5SL, 5.7, 5.8NA, 6.0NA, 5.5UNI, and 18SQ