Picture of Hands Free LED Light
I've bought 3 of these very bright Cred/LED lights from Lowe's for only $2.98 (batteries included)
I bought the large clip at Wal-Mart for $3.98.

The "O" ring is for railcar trainline air-hoses.
The ring fits snugly around the lens housing to protect the lens when walking along the narrow walkways on a locomotive.

I just secured the light to the clip using electrical tape, making sure the rear cap/switch is not blocked by the clip so the rear cap can be screwed off and back on to replace/recharge the 3AAA batteries