It's easy to make your own using the instruction from the internet. I did not use the circuit board stuff though. Just used the resistors and capacitors, some heat shrink tubing, and a little black electrical tape to help reinforce it some.
Looks like AM ripped of my design (from 2004), right down to the heat shrink tubing--more power to 'em!!!
You can make your own, a pair, for less than $5 (Harbor Freight has heat shrink tubing assortment for $1.99)--while you are there get a decent crimper--they have a full compression ratcheting crimper for $9.99, I've had one for 5+ years and used it A LOT!
Then go by your FLAPS and get some dielectric grease to fill the butt splices with before you crimp them.
Fill the splices with the grease, then insert the wires from both ends so that they mingle and overlap in the splice--then use the compression crimper, you will never have a problem with that connection.
Crimp connection problems arise when you do not use dielectric grease, do not mingle and overlap the wires (or worse crimp each separately, and worst of all using one of the el-cheapo "squashing" style crimpers...