KAKURI Jab Saw Folding 5-1/8", Japanese Pull Saw Foldable Keyhole Saw for Drywall, Wood, Woodworking, Plaster, Wallboard, Plywood, Razor Sharp Japanese Steel Blade, Made in JAPAN - Amazon.com
Klein Tools Folding Jab Saw 5.2-in Coarse Cut Drywall Saw in the Hand Saws department at Lowes.com