RZR Bio-BBs 6000 rounds 0.20g refers to 
a bulk pack of Nuprol RZR brand biodegradable 6mm airsoft BBs, weighing 0.20 grams each, typically sold in a large 6000-round bag for economical use, especially in close-quarters combat (CQB) or for environmental compliance, offering good precision (5.95mm +/- 0.01mm) and meeting ISO biodegradable standards. 
Key Features:
Brand: Nuprol RZR (a popular airsoft brand).
Type: Biodegradable (BIO), meaning they break down over time, ideal for outdoor use.
Weight: 0.20g, a standard light weight good for speed and indoor/CQB games.
Quantity: 6000 rounds, sold in a large, often resealable bag.
Precision: Tight tolerance (± 0.01mm) and triple-polished for consistent feeding and flight.
Standards: Meets ISO 14855-1 for controlled aerobic biodegradation.