Hex key - 5/16 inch allen wrench key for C42 / D48 / E60 tubeclamp fittings.
T-Style Allen Wrench - 5/16"
DISEN 13 Pieces Hex Key Allen Wrench Set SAE Size with Ball End, 1/20-3/8 Inch, Long Arm Ball Design, Chrome Vanadium Steel - Amazon.com
Luomorgo 5 Pcs 8mm/5/16 Inch Allen Wrench, L Shaped Hex Key Wrench, Heavy Duty Steel Hexagon Wrench Tool for Repairing, Installation - Amazon.com
TEKTON 3/8 in. Drive x 5/16 in. Long Hex Bit Socket SHB12408 - The Home Depot
5/16" Allen Wrench fits 3/8"SHCS & 1/2"Shldr Bolt
Amazon.com: Extra Long Allen Wrench Hex Bit Socket Set (10 Pack) - Long 6" Hex Bit in 3/8" Drive Sizes: 1/16", 1/8", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 7/16", 1/2" : Tools
Amazon.com: EKLIND 51920 5/16 Inch Cushion Grip Hex T-Handle T-Key allen wrench : Tools & Home Improvement
Professional EZ Travel Collection Extra Large Allen Wrench Jumbo Hex Key Set (SAE: 3/8", 7/16", 1/2", 9/16", 5/8", 3/4") - Amazon.com
2 Pieces HVAC Service Wrench Set 3/16 to 5/16 Hex Key Tools Hex Key Adapter for Straight Metric for Fixing Air Conditioning Refrigeration Device - Amazon.com
Hex Key Allen Wrench Short Arm 5/16" SAE Inch - QTY 25 | eBay
RAW PRODUCTS CORP Short Arm Black Hex Allen Key Wrench 5/16 Inch - Qty 25 - Amazon.com