The one I have is from ETB instruments. They have two different types of sensors which need wiring up differently. I have attached the two different wiring diagram types. If your speedo is an ETB give them a ring. I found them very helpful when I got the wiring mixed up when I put a new fusebox in.
ETB Instruments link https://www.etbinstruments.com
Speedo link 100mm Programmable Speedometer 200mph GT40