... ,φ14,φ16,φ1810*20,12*20,16*20,14*22,18*18,18*2210*20,12*20,16*20, ... Features of Beststeel Purlins:Adjustabel and exchangeab el C/Z purlins; automatic purlin fabrication line which has reached advanced ... and aperture can be prepunched according to requirement; for Z purlins, we recommend continuous overlappingEasy to install; no need ... % average cost cheaper than ordinary truss purlin C/Z Section purlin