Get the hand pump and two electro-cups at one low price. Purchased separately, they would cost you $40.00 or more.  The pump is made of heavy-duty plastic and pulls a lot of vacuum with little effort.  Now included a small power unit!!  Power box may vary slightly, depending on the manufacturer.

The base of each cup has a 1.3" opening, great for nipple, clit or even the head of your cock.  We will leave it to you imagination to use it for other body parts.  :)  Each cup is 2.75" tall and has a quick release one-way valve built into the top.  Once you are satisfied with the vacuum built up as you pump, simply pull it off and away from the cup and it will stay in place, providing that you have a good seal around the conductive silicone seal.  

Connecting to your lead wire is easy and takes an ordinary 2mm TENS pin.  This is a single-pole electrode, so you will need a second electrode attached to the other lead wire to complete the circuit.  A condutive silicone loop, TENS pad, anal/vaginal plug or any other electrode of your choosing will work to complete the circuit.

It is not recommended, for safety reasons, to use one channel of your power box and attach the two cups to each lead wire.  Current running across the chest can be very dangerous to your health.  Never use electrodes on the upper part of your body if you have a pacemaker or other medical device using batteries, as this could cause the medical devices to fail. Do not take that chance !! Additionally, do not use estim if you are pregnant.