Barrel tow release
The simple barrel tow release is very simple to attach to harness by just looping through your harness tow loops.
It is used with a short length of none stretch line with smooth splicing at each end so as to run easily through the ring at the end of the tow line. This forms an inverted 'V' shape with one end attached to each harness shoulder tow loop.
It is recommended that one harness attachment is made with a weaklink and the other with a tow release.
An even better solution is to use two tow releases so it is possible to get rid of the tow line if it was to become in some way caught at the metal ring.
Weak links. It is helpful for the pilot to be able to supply their own weak link in case there is a problem of a too strong weak link else where in the system. (Good pilots use very light or weak weak links as high loads should not occur with a good tow. Beginners might be tempted to use a heavy weak link after multiple weak link failures. This is extremely dangerous and it is highly recommended that you have your towing videoed and then correct the pilot error and do NOT change the weak link for a stronger one.)
It should be remembered that as the short line is doubled then a weak link of only half the strength is required in one side of the V.
Note: The only know short coming of this type of release is that it is more difficult to release in a line slack situation. The spring loaded double line release used for winch towing is generally considered far quicker to release in a loose line situation.