Forney 70469 Nylon Tube Brush with Wire Loop Handle, 8-1/2-Inch-by-3/4-Inch

The overall diameter of the bristles is just under 3/4", with the bristles covering an area of about 3". The brush itself measures end to end about 8 3/4". Stiff bristles - exactly what I was looking for. Handle is a bit short, but that loop at the end is perfect for slipping a finger into and holding it while brushing vigorously! Twisted metal wire is not painted or coated so probably will eventually rust.

If you have an Aeroponic Tower Garden - you need this! Every so often you need to take it apart and clean the build up of slime from your tower. That is easy except for the tube that takes the water up the tower. But this little brush fits perfectly into each section and is sturdy enough to make the work go fast.

Worked great - used it to get rid of biofilm in the shower drain and other drains around the house.

very flimsy