Silicone rings, very comfortable and safe around machinery and electrical.
ThunderFit Silicone Rings, 7 Pack & Singles Wedding Bands for Men - 8.7 mm Wide https://www.amazon.com/dp/B06XBX9BGN/ref=cm_sw_r_cp_apa_6d.UBb4G4PWZ6
Thise rings probably cost a nickel a piece to make. Competition will be eating his lunch less than 6 months from now.
I mean, absolutely good on the guy for capitalizing on the idea when he could. I just hope he's already started socking money away into his next idea or set for an early retirement by now.