It is important to change these filters frequently on this model, otherwise the machine will not always function properly. The Dyson LBK 3 Pack Pre-Filters are an exact replacement and at an exceptionally affordable price there is no reason to be conservative with them. It is recommended that these filters be replaced every two to three months and at the low price of three filters this not only makes sense but is a good idea and protects your Dyson. has worked well for many years.