Need to find replacement Shimano UN-300 68 TH. 68x118mm.

I recently had a bottom bracket completely disintegrate and need to find a replacement. I can find the same style shimano BB with the same dimensions but I cannot seem to find the exact replacement as many of them are listed as “68 TK” or some other combination of letters as opposed to “68 TH” of my BB. I am wondering if anyone has any info or can help me resolve this. Thanks.