ABC :
FAST ACTION CERAMIC, Rated 250V for 20A or less, and 120V for above.
1/4" x 1 1/4" (6.4mm x 31.8mm)

AGC :
FAST ACTION GLASS, Rated 250V for 10A or less, and 32V for above.
1/4" x 1 1/4" (6.4mm x 31.8mm)

AGX :
FAST ACTION GLASS, Rated 250V for All sizes.
1/4" x 1" (6.4mm x 25.4mm)

MDA : TIME-DELAY CERAMIC, Rated 250V for 20A or less, and 120V for above. 1/4" x 1 1/4" (6.4mm x 31.8mm)

MDL :
TIME-DELAY GLASS, Rated 250V for 8A or less, and 32V for above.
1/4" x 1 1/4" (6.4mm x 31.8mm)