Ravin Xbow R18 .003 Polymer Nock Arrow - 6 Pack. 003 6PK Specifications for Ravin .003 R18 Arrows: Manufacturer: Ravin Color: Black Quantity: 6 Length: 16 in Finish: Brass Weight: 350 grain 350 g Nock Type: Ravin Clip-on Nocks Fabric/Material: Carbon Straightness: 0.003 in Features of Ravin .003 R18 Arrows High-profile offset vanes 2 in High-impact brass threaded inserts High-impact aluminum nock bushings Ravin-engineered polymer nocks 6 pack arrows for use with the Ravin R18 crossbow only. Package Contents: Ravin .003 R18 Arrows Ravin R146: Xbow R18 .003 Polymer Nock Arrow - 6 Pack