A calf machine refers to a piece of gym equipment designed to specifically target and strengthen the muscles in your calf area, which is the lower part of your leg. Full definition
If you do not have access to a seated calf machine you can perform a similar exercise using an exercise bench, a step and resting a weight plate across your knees. (fitnessandpower.com)
You may also use a standing calf machine for this exercise. (muscleandbrawn.com)
In order to perform this great calf exercise you will have to use rotary calf machine. (bodybuilding-wizard.com)