You can get a Dye Hyper 3 which has the older style threads to fit a PM6. When you order one, you will need to let the retailer know what marker it is for.
I do not think you can get the Proto style Hyper 3 seperately yet.
If you want another option, you can buy a CP reg which will do the job equally as well. Once again, let the dealer know what marker it is for.
Both items can be purchased from
all good dealers. I don't think they have them on their site, but you can phone up and order over the phone.