The "CUSTOM HERITAGE 91 BLK, MED

The "CUSTOM HERITAGE 91 BLK, MED" refers to the Pilot Custom Heritage 91 fountain pen in a Black (BLK) finish, specifically with a Medium (MED) nib, often available as a Soft Medium (SM) for a smoother feel. It's a popular Japanese pen known for its classic design, smooth 14k rhodium-plated gold nib, and excellent value, typically coming with a CON-70 converter for ink.