They have their own wire handle and are convenient for small jobs or for tight spaces. Can be used over and over when properly cleaned. Economical enough to keep several on hand. Available in package of 1 doz. They're low in cost, so keep several sizes on hand.
Larger sizes have a pour spout.
The unpainted handles make them ideal for resin application where dissolving paint can contaminate the resin. Also use for glue and stain application, and cleaning with solvents. Get several dozen, you'll find lots of uses for them. These professional bubble busters are a must for applying mat in fiberglass laminates. The rollers eliminate air entrapment and prevent pulling the mat to shreds.