1)Thermal StabilityPlane-type    260 ° CTrough-type  260 ° CTube-type 200 ° CSingle slot-type   200 ° CPrism-type    200 ° C

2)Compressive strength (pressure test)Plane-type      6.27 MPa (64Kgf/cm ²) 8.33 MPa (85Kgf/cm ²)                      15.68 MPa (160Kgf/cm ²) 31.36 MPa (320Kgf/cm ²)Trough-type   4.41 MPa (45Kgf/cm ²)Tube-type      1.57 MPa (16Kgf/cm ²)Single slot-type     2.45 MPa (25Kgf/cm ²)Prism-type          2.45 MPa (25Kgf/cm ²)

3)Chemical Stability:

Water resistance: <=0.5mg/dm ²

Acid resistance: <=0.5mg/dm ²

Alkali: <=80mg/dm ²

transparent level gauge glass