These are manufactured by E3D and are provided to West3D by LDO Motors, who has designed these specifically for length to fit toolheads with toolhead boards without the need for splicing or doing extensions. The length of the thermistor (JST-XH) connection is approximately 17cm, and the length of the terminated (Ferrule) heater connectors is approximately 13cm.

• Experience even faster heating and ability to print and hold at higher temperatures with this upgraded 60W heater core from E3D
• The HeaterCore secures onto a Revo-compatible cold side using a Revo HeaterCore spring (included). After its attached, just screw in a Revo Nozzle and youre ready for simple, tool-free nozzle swaps that dont need hot tightening.
• Heats up much faster than a typical heaterblock. Its designed to be much safer, too a positive temperature coefficient (PTC) means power reduces as it gets hotter, reducing hazards in the event of a thermal runaway.
• Compatible with many popular 3D printers such as Creality CR series and Ender series, Prusa, Anet, Biqu, Monoprice, and many more.
• Learn everything you need to know about the Revo HeaterCore in E3D’sblog.

Unsure on the voltage you need? E3D has a nice page to help you identify the voltage from your power supply:https://e3d-online.com/blogs/news/12v-vs-24v