These items are A FEMALE Cam Lock Repair Fitting in sizes 25mm - 35mm - 50mm for use with the same size IMER hoses.  To install cut the hose which is usable and insert this piece into the hose. Use the approved hose clamps clamps to secure Cam Lock fitting in place.  Be aware that these repair fittings have an internal barb that will reduce the inside diameter of the Hose.