12mm x 90cm SnapLok Solid Nylon Rod - STIFF
 
The 12mm Solid Nylon Liner stiff rods are quadruple crimped to the fittings/ferrules, they are corrosion resistant as they are solid stainless steel with double buttons for double security, unlike aluminium that pits and eats the metal if cleaning solid fuel/smokless flues.
 
These are grey in colour to distinguish themselves from the more flexible standard white 12mm rods
 
These rods are still flexible for tight bends and ideal for 5" to 8" flues for multifuel, oil, gas, biomass flues and duct cleaning rods.
 
These rods are 90cm in length, the reason being is that the thinner rod you use at a long length then is looses its rigidity and can cause 'liner slap', stress the rod and eventually snap. So we found after much testing, a slightly stiffer but still very flexible rod is a better rod at 90cm and can get round 90 degree bends with ease. 
 
Using a combination of standard 12mm liner rods and the stiff 12mm rods works well in liners, for example 5 - 6 x standard 12mm liner rods, then follow up with the stiffer 12mm liner rods.