J-slot cpj ø125 mm superpro porcelain tiles diamond blade. the j-slot cpj dry cutting diamond blade by for porcelain tiles is specially designed to offer the tile fixing professional the best performance.the cpj diamond blade is particularly recommended for straight cuts in porcelain tiles and especially in those jobs requiring a high cutting speed without sacrificing high levels of performance and quality. because of its reduced thickness, the cpj diamond blade by is not recommended for mitre cuts