You can also get IR filter from TK Foto.
I think they have new stock for the Kenko Pro1D R72 for 67mm, 72mm and 77mm.
Basically the same as Hoya R72 which is my favorite IR filter due to the fact that it pass thru the right amount of IR and colour lights that I like.
The resultant image is also easy to manipulate and do channel swap if desired.