Cov khoom tuav tau raug xa mus rau cov ciaj ntswj nyob, thiab lawv qhib qhov dav tuaj yeem hloov kho nyob rau qee qhov, uas yog ib qho cuab yeej siv los ua kom nruj thiab qheb rau cov sib txawv. Cov cuab yeej siv hluav taws xob hloov kho yog cov neeg ua haujlwm txij nkawm, vim tias kev qhib meds bolts, tab sis kuj yog rau qee lub hauv tsev tsis- txheem bolts.
Tus tsim khoom ntawm cov pob zeb uas tau kho tau yog Swedeable Warhan Petter Johansson (1853-1943), uas tau tsim cov ciaj ntswj hauv 1892.
Cov kab hlau kho tau yog tsim ntawm ib lub taub hau thiab lub taub hau, thiab lub taub hau yog tsim ntawm cov ntaub nyias nyias daim di ncauj, ib lub qhov ncauj ntawm lub phaj, ib lub qhov ncauj phaj, ib lub turbine thiab tus ncej puab. Lub teb tig tshuab hloov kho qhov loj me ntawm cov phaj av. Cov lus qhia tshwj xeeb yog qhia tawm hauv qhov ntev × chaw qhib (chaw: hli). Cov hluav taws xob feem ntau siv plaub qhov tshwj xeeb: 150 hli × 19mm × 24mm × 30mm × 35 hli × 36mm (12 ').