IBM ServeRAID Quick Reference page 5

Same as ServeRAID-3H adapter except battery backup module is standard
ServeRAID-4L (part 37L6091, 2000)
US Announcement Letter:
Visual identifiers:
One external VHDCI connector
One internal 68-pin industry-standard SCSI connector
Space for two internal connectors, but only one present (same circuit board as the 4M)
ServeRAID-4Lx (part 06P5740, 2001)
US Announcement Letter:
Visual identifiers:
Half-length card
Square heat sink in the middle of the card
One external VHDCI connector
One internal 68-pin industry-standard SCSI connector
100-099
101-146