Prime-Line Products PL 7727 Screen Frame Corner, 5/16-Inch X 3/4-Inch, Gray Plastic, (Pack of 4) Fits 3/4 inch x 5/16 inch aluminum screen frame material Plastic corners are used to assemble 5/16 inch thick aluminum screen frames Square-cut system provides for fast construction and easy installation Miter cuts (frame material cut at 45 degree angles) are not necessary with these corners This item includes 4 corners per pack Plastic corners are used to assemble 5/16in. thick window screen frames Square-cut installation for fast and easy construction Gray Vinyl Construction Durable Plastic Material