Simply Cycling 29 Inch x 2.1 Inner Tube with Presta Valve

Simply Cycling CC014 Inner Tube, 29 Inch, Presta ValveTwenty nine inch, often called 29er, is the wheel size that became the mountain bike standard through the 2010s, valued for rolling over obstacles more easily than smaller wheels. This tube is the 2.1 width, a common tyre size for cross country and trail 29ers. Simply Cycling Inner Tube is made from butyl rubber and air leakage tested, so it holds pressure between rides.Which valve do I need?This is the Presta version, the narrower valve most often found on performance and mid-to-high spec mountain bikes. It is sometimes called a French valve, and it needs a pump head suited to Presta, though most modern track pumps switch between the two.The way to check is to look at the old tube or the hole in the rim. A Presta valve is narrower, around 6mm, with a small nut on top that unscrews to let air in. A Schrader valve is wider, about 8mm, with a small pin in the centre and a threaded outer sleeve, the same type used on car tyres. The rim