1. Screw cap and sealing performance
Cap material: PP or HDPE, transparent/color optional.
Sealing method:
Silicone/PE film inner pad (leakproof, suitable for liquids).
No gasket (special for dry samples).
Anti-opening design: Optional anti-theft ring (breaks when opened for the first time).

2. Physical properties
Temperature range:
PP material: -20℃~121℃ (autoclavable).
PET material: -20℃~70℃ (not autoclavable).
Transparency: Highly transparent (PET is better) or translucent frosted (PP).
Chemical compatibility: resistant to water, alcohol, weak acids and alkalis (strong solvents need to be tested).

3. Special design options
Tube bottom type:
Flat bottom (stable when placed upright) / conical bottom (convenient for centrifugation).
Tube body marking:
Laser scale (1ml interval) or label area (frosted surface).
Color coding: optional cap color (such as red/blue/green to distinguish sample types).