... . C-channel size: 38 x 10mm, 30 x 27mm, 50 x 12mm, 50 x 15mm 2. Cross Stud size: 50 x 19mm, 25 x 19mm 3. Length ... x 40mm, 50 x 35mm, 75 x 25mm, 75 x 35mm, 75 x 45mm, 100 x 45mm 2. Track size: 50 x 40mm, 50 x 35mm, 75 x 30mm ... , 75 x 40mm, 100 x 40mm ...