“We ordered the ring sizer and received it from you, measured my finger and sent the size off. The ring which came was too big, and slipped off once or twice. I've no idea why, but maybe you could give some more precise instructions eg how tight should the ring be. If I'd bought it from a shop this wouldn't have happened.”
“The ring sizer was great, helped me order the correct size with confidence. Wear it around for a day or two and check your measures at different points of the day. Much better than just slipping one on at a jeweller.”