Amazon with IMENSEAS Direct has the 7-Piece IMENSEAS Hand Grip Strengthener (Black) for $18 - 7% off coupon (check "Save an extra" box) - $3 off with coupon code 4AF995D7 [Exp 1/21] = $14 with free shipping on $25+ or with Prime.

Includes a hand gripper, finger stretcher resistance extensor bands, finger exerciser, grip strength ring & stress relief ball.