VTL MB-450 B+ Fuse

The B+ fuse blew on one of my MB-450's this week; the fuse in place was a Limitron KTK-2.

Today I found a shop with a KTK-R-2, the guy said they were the same, both are 2 amp fast blow. The spec sheet I found implies the "R" stands for Rejection and allows it work in a wider variety of fuse holders (the R has a 'nipple' at one end but it would still fit in the VTL holder). Other specs are very similar, they both measure about 1/2 ohm resistance.

Does anyone know anymore about this R series and whether it could be used in the VTL.

Thanks,
Bruce