The McAlpine WC-CON4B is a rigid WC (water closet) connector designed to connect a toilet pan to a 4"/110mm soil pipe. It has a 97-107mm inlet, which means it can fit a toilet pan with a spigot diameter within that range. The outlet of the connector is 4"/110mm, which is the standard size for a soil pipe in the UK. The 40mm offset refers to the distance between the centre of the inlet and the centre of the outlet. This offset allows the connector to be used in situations where the toilet pan outlet is not directly above the soil pipe. The offset enables the pan to be positioned slightly to the side, which can be useful when dealing with awkward plumbing layouts. Overall, the McAlpine WC-CON4B is a reliable and durable solution for connecting a toilet pan to a soil pipe in a range of different situations. It is a popular choice among plumbers and DIY enthusiasts alike, and is easy to install provided you have the necessary tools and expertise. ・ Available with finned outlet for 4"/110mm PVC-U and cast iron soil pipe diameters (internal), and with plain end outlet to fit 110mm soil or underground pipe fittings ・ 97-107mm Inlet suits all pan spigots ・ Adjustable Length ・ Complies with BS 5627:1984 and DIN 1389-2 ・ Manufactured in Polypropylene