Dab tsi yog vim li cas rau cov blockage ntawm cov dej phwj dej twj tso kua mis
Submersible dej phwj yeej yog dav siv nyob rau hauv cov chaw nres tsheb, thiab lwm qhov chaw ua haujlwm, chaw pw hauv tsev, ib qho yooj yim, thiab tsis muaj suab nrov. Lub nqus dej twj tau muag hau...