Dial glass for SX-1250 and SX-1280.  Same size as the original glass with the hole bored for the tuning knob.  Made from single pane window glass.  I have sold over 100 of these without issue.  I choose USPS Priority mail because it is insured and only a dollar more than USPS ground.  UPS is much more money as well as FED EX or DHL.  I do not mark up shipping and pay for all packing materials.
To install first center tuner shaft in the hole by using masking tape.  Mark on the back of face plate with a felt marker glass edges.  Remove masking tape and center glass. You can use double back tape on the edge or apply E6000 adhesive found at any hardware store.  Place some weight on the glass such as books till adhesive or tape cures.