Amazon has the 7-piece Blackstone 5515 Egg/Omelet Ring Kit on sale for $24 - $7 off coupon (click checkbox) = $17 with free shipping on $35+ or with Prime. Useful on griddles, dishwasher safe. Includes:

• 3 Round Egg Rings (4" diameter)
• 3 Square Egg Rings (4" diameter)
• 1 Omelet Ring (8" diameter)