... your requirement,we have normal corners as follow:6 way corner,the normal size is 300*300,400*400mm. ... 4way and 5way corner for the roof system connect,the size is 290*290mm ... ,300*300mm,400*400mm. T-corner for the beams and roof connect,the size is depend ... the size of beams Down corner is a part of roof system,connect with beams.