All the advantages of the A Series syringe plus:
The A-2 features a push-button valve, which allows sample storage to 250 psi in syringes as small as 25 µl. This is useful with small liquid samples containing low-boiling components which would be lost through evaporation using ordinary syringes.
The positive rear stop (in 250 µl and larger sizes) prevents plunger blowout at elevated pressures, protecting against sample loss or operator injury. In addition, the A-2 syringe has all the standard Pressure-Lok features such as a PTFE plunger tip, PTFE-sealed needle, and ultrasmooth bore. Replacement components are available for easy repair.