The IPAF training categories, with abbreviations and brief explanations, are:

Static Vertical (1A): Vertical personnel platforms (static)

Static Boom (1B, 1B+): Self-propelled booms (outriggers), trailers/push-arounds, vehicle-mounted platforms

Mobile Vertical (3A, 3A+): Scissor lifts, vertical personnel platforms (mobile)

Mobile Boom (3B, 3B+): Self-propelled booms

Push Around Vertical (PAV): Push around verticals

Special (SPECIAL): Specialist machines

Mast Climbing Work Platforms (MCWP) 

Insulated Aerial Devices (IAD) 

Harness Use and Inspection (H)

Loading and Unloading (LOAD)

MEWPs for Managers (MM)

CONSTRUCTION HOISTS (CHs):

Goods Hoist (GH)

Transport Platform (TPH)

Passenger Hoist (PH)

What the "+" symbol means
This means that the operator has successfully completed the PAL+ course, which covers additional, practical training and testing on the machine category indicated. The operator has successfully demonstrated his/her ability to operate powered access equipment safely and effectively in challenging work environments.