Compare Semroc Centering Rings Fiber BT-1+ to BT-5(2pk) RA-1+-5 * Semroc Centering Rings Fiber BT-1+ to BT-5(2pk) RA-1+-5 1 pack ID= 0.250" OD= 0.516" 0.0… Now: $0.79 Add to Cart