The two brand new Volcano stems feature an overall wider clamping area, anti-slip grooves along with wider bolt heads, all to help increase holding power & keep your bars exactly where you want them. They also feature some very clean machining, not only to save weight but also give them a personal look & help set them apart from the sea of very similar looking stems out there section Product Specs TYPE: Top Load REACH: 50mm RISE: 30mm CLAMPING DIAMETER: 22.2mm WEIGHT: 361g