This one is a Michelin AirStop butyl tube, 700x18-23c with a 52mm Presta valve. I pump it up to 130 psi as the tire is marked with this rating, and then I don't regularly check the pressure because my tire pump doesn't seem to do this well (when I put the valve on a full tube's valve, the gauge reads zero, until I start pumping air into it and the gauge starts reading higher; this seems to create a risk of over-inflating while trying to get an accurate gauge reading).