Brand x seat clamp boltthe brand x seat clamp is simple strong and lightweight the collar is forged from 6000 series aluminium and uses a cro mo bolt with 5mm allen key fitting to securely fasten your seatpost at your desired height it is available in 318 or 349 sizes and comes in durable anodised black of silver featuresmaterial 6000 series alloysizes 31 8mm or 34 9mmfinish anodised black or silver finishweight 20gbuybrand x componentsfrom chain reaction cycles the worlds large