There are many different manufacturers offering different valve bodies. The T/A was one of the first to use an internal solenoid release. Early Lamb versions had an external solenoid and didn't work all that well. Supposedly the T/A VB that I have, an early version, is not good for a pro tree. I can however cut .4teen lights with it if I don't use a two step. Otherwise it's a .500 tree brake.
Since then there are many others with various features, Griner, JW, TranzAct, Hipster, TCI and so on.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
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