Mini Chain Knockers: For really small diameter pipes of DN32 (1 ¼”) - DN50 (2”) with or without tight bends we recommend the Mini Chain Knocker. It only has one hub where both of the short chain links are attached - making the chain easy to navigate through tight spots. 1-Chained Chain Knockers: The decision between 1-Chained and Mini Chain is really close call since both are very agile with navigating through bends. Here, the chain is multi-link (longer) chain, offering a bit more cleaning area in one run when compared to the Mini Chains. Having only 1 chain and a hub in both ends, it lacks bulkiness and basically navigates effortlessly through wherever the flex shaft does. So, the 1-Chained option is great for small diameter pipes and bends while offering size options up to DN75 (3”) 2-Chained Chain Knockers: These Chain Knockers offer a middle ground between 1-Chained and 3-Chained options. They are effective at descaling but moderately capable of navigating through bends. 3-Chained Chain Knockers: The 3-Chained option is usually the option to go with when the descalable line is quite straight with long bends / without tight bends. 3-Chain offers thorough and effective descaling with a moderate cost in flexibility. Circular Chain Knockers: Circular chains are often wrongfully ignored. They have the niche of offering powerful cleaning & descaling over the full pipe circumference while being gentle to the pipe. It is an excellent choice for example when facing a pipe in poor condition and you want to minimize the risk of damaging it even more while still being able to clean it. Circular Chain Knockers are usually the most bulkiest chain knockers, so you might struggle if there is going to be navigation through multiple bends or singular tight turns. Circular Chains impose much less strain on the pipe walls as the centrifugal force rotated tool cleans the walls of the pipe without slamming into them.