8 Automatic Toilet Bowl Cleaner Stain Remover Blue Tabs Tablet Flush Tank New. This automatic blue bowl cleaning tablet cleans and deodorizes with every flush. Each tablet measure 2" diameter approx. and are safe for all plumbing and septic tanks. It cleans the tank, rim, inner wall, water pipe and other parts of the toiler thoroughly and makes your toilet bowl clean and bright, safe for use with bleaches and cleaners. Effective in cleaning the toilet and sewer pipe, preventing the and sewer from being infected.These tablets are effective in deodorization, purify the air of the toilet. Easy to use: just take out 1 cleaner, put in the far end of the tank from the water outlet. Listing is for 2 packs, making a total of 8 pcs.