The cartridge is a Pickering V15, it's a V15H / V15HB and were standard fitment for KLH systems.
It was an OEM fitment for the 3000 headshell and has a single hole fixing at the front. It takes standard V15 styli.
If you look at post 9 in this thread there are photos, including modifying a Garrard 2025TC to take one of these cartridges.
https://www.vintage-radio.net/forum/...39#post1024339