The McAlpine WC-F23RV is a flexible toilet connector designed to connect a toilet pan to a 4"/110mm soil pipe. It has an inlet range of 97-107mm, which makes it suitable for a range of toilet pan sizes. The connector also features a 1.25" universal vent boss, which allows for the connection of a soil vent pipe. This helps to prevent the buildup of pressure in the waste pipe, which can cause unpleasant smells and potential blockages. The flexible design of the connector allows for some movement and adjustment during installation, which can be helpful when connecting a toilet to a soil pipe that is not perfectly aligned.