These use adjustable nipple clamps and each clamp has a 6 ounce metal ball hanging from a short chain. These spiked balls are 2" across with 1/2" spikes making the total measurement 3" across. They are made of a lightweight metal and still weight 6 oz each. If these were made of a heavy metal like lead or steel they would probably weigh well over 2 lbs each.Price $29.95
S&H $6.00 USA, $12.00 international