Manthorpe GPD-JU-6 4-Way SmartDrain Junction Black - Pack of 6 The Manthorpe SmartDrain Junction Unit can be used to make a 90º corner, T-junction or cross when laying the SmartDrain system. The product has thinned outside walls which can be easily removed with a craft knife. Simply remove whichever and however many sides are required and connect to the rest of the system with the easy to fix clips. Available with a black or silver grate. Properties Can be trimmed down easily. Makes a 90° corner. T-junction. Or 4-way junction. Available with black or silver grate cover.