pentagon shower tray is one that has five sides. Shop Pentagonal Shower Trays at Bathroom Shop UK. A pentagonal, also known as a pentangle, the shower tray is used as a base for a pentagonal shower enclosure. If you are looking for purchasing a shower tray for your enclosure online, check out our full range of shower trays here. We stock a huge range of square, quadrant, rectangular, offset quadrant shower trays at affordable prices. Best Bathroom deals on the best bathroom brands! Here at bathroom shop UK, we also stock the full range of shower trays to match with shower enclosures.