Johnston Fishing Jars (hydraulic jars) deliver impact at any hydrostatic pressure and they hit quick, hard and long – even at bottom-hole temperatures up to 400 degrees Fahrenheit.
Allows continuous hitting at any hydrostatic pressure
Damage-resistant delay mechanisms allow faster jarring
Aircraft-quality, AISI 4340, electric furnace steel in all critical parts for durability
Up to 5/1000 of an inch