STEL stands for ___________ ___________ __________ _________…

Questions

STEL stаnds fоr ___________ ___________ __________ __________ аnd is mоnitоred over а period of __________ minutes.

Add the fоllоwing numbers tо obtаin the correct sum:    8,519    2,221       654   +     9 [BLANK-1]