Cable with Neutrik Speakon connector

I recently acquired a REL Strata iii.  It is awesome with my Acoustic Zen Adagios.  However, I would like to find an upgraded cable with the Neutrik Speakon connector.  Any suggestions where I can find one?  Thanks.
Signal Cable is advertising REL cable with Speakon connector for $90. Look up REL in search function.
I have tried the Signal cable with ny Strata iii. There was a great improvement over the stock REL cable. I since have upgraded to the Synergistic Research cable, better than the Signal. But for the money the Signal is very good. And Frank in a true gentleman to work with.
If you have a cable you like, this is a very easy DIY project. I bought my REL sub used and the seller neglected to include the cable. Piece of cake to build one.
I had a Signal Cable one but it came apart; I now use 2 made by an Audiogon member who use to advertise on here; they are considerably better. I will try to find his name.
Neutrik Speakon plugs are very cool...been using them on pro gear for years. I did find an angled Speakon plug that is great for my REL (less stress on everything) and I had fun making the cables...much less expensive that way...shrink wrap tubes galore, and, weirdly, the plugs are made in Liechtenstein!
I have a Nordost Baseline made to Rel spec. Huge improvement over the stock cable. If memory serves me there was a $35 upcharge to make it to Rel spec a couple of years ago.
It is member Zikhmark; see his ad and feedback. I recommend him.
Speakon connectors are very easy to work with. They have set screw type internal terminations and come with two sizes of inserts to use as strain relief. I just made two different umbilical DC power cables with Speakon connectors to connect an outboard power supply to a preamp. For one cable I used bulk power cable and for the other I used bulk IC cable. These are terminated with Speakons at both ends.

I assume the REL comes with a Speakon input? If you know what cable you want to use, you could easily reterminate it with a Speakon connector, which is easily (and inexpensively) available from Parts Express. If you want to try a variety of different cables with your new sub, you could consider wiring up a Speakon connector to some short hook-up wires and then terminate those to a standard rca connector input (I assume you are connecting a standard low level sub cable?). An inexpensive rca input connector should also be available from Parts Express. Using that "adaptor" set-up, you could try a variety of sub cables that have standard terminations until you zero in on what you want, and then reterminate the REL end of that cable directly to a Speakon connector. I would try something like that before paying a bunch of money to have someone make a cable that I haven't heard before, or to pay to have someone reterminate cables for me.