The size of these inner tubes is 2.75 / 2.50 - 12.
This means it will fit either a 2.50 tyre or 2.75.
Generally used on the front but can be used as a rear on some models
Fits wheel rims with a diameter of 12 inch and a wheel width of 2.50 - 2.75 Inch
This is a common size for front 12 inch tyres.
It incorporates a standard straight Schradar valve Chinese import bikes
including Stomp Demon X WPB Orion M2R Lucky MX Thumpstar Explorer Braaap Atomic Pitpro Pitster Pro DHZ,SSR Piranha and many more have all used this size at some time
Valve Type Straight / Inner Tube Size 2.75 / 2.50 – 12