Free weight
A free weight was a tool used for weight training, not connected to a larger training apparatus. Free weights were common offerings in gymnasiums.

Commander Jack Ransom had a large collection of free weights, noting that if he was to be court martialed, he would need sufficient time to pack them. () Ransom brought free weights with him to train during down time on a covert mission to a Pisepian agricultural colony. () 
Sporting equipment