This is one roll of 1000 1/2" Pex-Al-Pex tubing.This tubing is primarily used in radiant heat applications along with other heating applications.Pex-Al-Pex tubing is different than regular PEX tubing. Pex-Al-Pex tubing is constructed with a layer of aluminum in between two layers of PEX and as a result is a 100% oxygen barrier tubing. While PEX has UV resistance, it should not be placed in the sun or have UV exposure.This tubing can be used in most radiant heating installations such asThick/Thin concrete slabsUnder sub-floor (between joist) with or without heat platesEngineered FloorStaple up or Staple downBaseboard and RadiatorSnow Melting SystemsSolar Heating ApplicationsCompatible with the following fitting typesPex-Al-Pex Compression FittingsPex-Al-Pex Press FittingsDoes NOT work with regular PEX fittingsCertifications/Ratings/ApprovalsASTM F1281 StandardNominal Size - 1/2"Inside Diameter - .472"Outside Diameter - .629"125 PSI at 180F25 year Warranty on all PEXworx Tubing.