<!--014-->Rubber O Rings - 4mm (X 50) <!--014-->Rubber O Rings - 4mm (X 50) Rubber O Rings - 4mm (x50) 4mm rubber O rings, pictured with a 5p £2.00 Out of stock. Pack of 50 4mm rubber O rings, to fit our 4mm rubber cord. These rubber O rings can be used for spacers, or as a neat finish to each end of a row of beads. NB: The fit of these O rings is slightly loose on our 4mm cord. So may not hold the beads in place quite as well, as is the case with the 2mm O rings on our 2mm cord.