Vintage soviet Erlenmeyer flask

The engraved letters ???? on this Erlenmeyer conical flask means «Transparent Thermostable Tubular Eye» (according to GOST Soviet technological marking of the glass type). This abbreviation was applied to chemical laboratory glassware produced in the ussr in 1970s-80s. The marking indicates a heat-resistant and chemically-resistant glass, capable of withstanding sharp temperature changes and exposure to aggressive reagents when heated on a laboratory burner.
A beautiful glass relict from laboratory in 1960s-70s.
Measures: height 10cm, 6.5cm wide.