I have a nice Tuthill No Du Kap for a C11. This is rigid plastic (holds its shape, unlike the Velcro & foam jobs) and is felt-lined, with a built-in heating element. It can be run either directly from 12VDC or through a Kendrick or Dew Buster controller. They sold for about $150 plus shipping; take this one for $100 shipped CONUS. I accept Paypal (no surcharge) or postal money orders. Astromarters with great feedback can send a personal check.