Brick Colorstream
PA (Polyamide)
Polyamide, or nylon, is a very strong plastic that holds up against high impact, lending itself to connectors and gears, even in non-LEGO machinery, where durability is more important than perfect coloration. LEGO used nylon as far back as the 1960s for flexible vehicle couplings (pictured right), although today most of these have hardened and are very brittle. Modern Technic bricks with pins, such as 42929, are dual-molded so the brick part is ABS and the pin is PA (this is why they show up in BrickSet as “multicombination”, even though it’s the same color throughout).
Only the earliest clip plates (from Classic Space sets) use this material. I would guess that modern ones use PC.
PA (Polyamide)
Polyamide, or nylon, is a very strong plastic that holds up against high impact, lending itself to connectors and gears, even in non-LEGO machinery, where durability is more important than perfect coloration. LEGO used nylon as far back as the 1960s for flexible vehicle couplings (pictured right), although today most of these have hardened and are very brittle. Modern Technic bricks with pins, such as 42929, are dual-molded so the brick part is ABS and the pin is PA (this is why they show up in BrickSet as “multicombination”, even though it’s the same color throughout).
Only the earliest clip plates (from Classic Space sets) use this material. I would guess that modern ones use PC.