No Tangle Dog Leash Coupler, Dual Double Dog Adjustable Splitter Lead for Two Dogs Durable Walker $4.99 from Amazon

Wow, the first review is interesting.

This is worth slightly more than the price I paid for a similar product from Amazon ($0.54) which is unfortunately not available currently. However, you can get this for about $2-3 from eBay and this also the regular price in other listings on Amazon; it's the exact same product except branded with someone else's private label.

A few issues with most of these generic snaps:

1. Spine seems thick based on the photo of the snap on its side, however it's only about 1/4" thick. Probably won't matter unless you have a large or a very strong dog (GSD or similar size).

2. Typically warped such that the gate doesn't close completely flush, can be an issue, usually isn't.

3. Main problem: Thumb latch forms a 90 degree angle such that it protrudes directly out from the snap. This causes it to catch easily where slightly more expensive snaps have a beveled edge that slides off or otherwise deflects incoming objects. See the photos that show how these types of snaps come off the D-ring by themselves when, for example, a dog shakes itself off and it jangles around what it's connected to. The photos show the exact same snap except painted black.