Need a cable for thunderbolt external hard drive

You should provide a direct link to the manufacturer's product page and documentation for the exact model drive you have. I tried a quick search, but I don't see any hits for "gen4" on WD's website. There are a lot of G Raid drives shown so I don't know which one to look at.

You need to check the product documentation & data sheet for your exact specific model. Check what transfer protocols your drive supports using the USB-C ports. Different variations of even a Gen4 model may support different transfer protocols. Avoid the marketing hype as it usually misleads people....look at the actual documentation. If the documentation does not specifically mention USB3, USB4, or Thunderbolt, then the product does not support that protocol regardless what the marketing hype says on the product page.

Once we have a link to the product documentation and also know the exact model of your Mac, then we can provide you with more accurate information since this can be confusing. To get the exact model of your Mac, click the Apple menu and select "About This Mac".

Which specific G-Raid drive do you have? What ports does it have?

If it is a Thunderbolt 3 drive, you'd need a Thunderbolt 3 or 4 cable (with USB-C plugs on both ends) – and in that cases, chances are that you would already have and be using one.

Thunderbolt 1 and 2 lived on the Mini DisplayPort connector. There is an Apple Thunderbolt 3-to-2 adapter that can help you connect a Thunderbolt 1 or 2 device to a current Mac. It only translates Thunderbolt protocol, and it does not carry power from one side to the other, so you can't use it to directly attach bus-powered drives.

Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple

If your drive has a USB port, in addition to its Thunderbolt port, that might provide an alternate way of connecting it. There are many ways of going from USB-C (USB) to USB-A (USB), including

• USB-C to USB Adapter - Apple, which takes up one USB-C port to give you a single USB-A one
• Hubs with multiple USB-A ports which connect via USB-C
• More advanced USB-C and Thunderbolt docks that provide several types of things, including USB-A ports

Your MacBook Pro has Thunderbolt ports (the M4 MacBook Pro has three TB4 ports and the M4 Pro and M4 Mac have three TB5 ports) , so if your external drive also has Thunderbolt, not just USB, any cable certified for Thunderbolt should work, though confirm with G Raid what it supports. There are a number of vendors and any good computer reseller should carry TB cables.

Regards.