2 Pack Replacement Filters for Nuaire MRXBOX95-WM1 Dimensions: 175mm x 270mm 2 Pack Replacement Air Filters suitable for Nuaire WM1 MVHR system Nuaire Filter Product Codes: MRXBOX95-WM1 MRXBOX95AB-WM1 If you're not 100% sure which filters you need, we recommend you check the dimensions of your filters against the product description before placing your order.  Filters must be changed a minimum of every 12 months but this is subject to the environment in which you live. Filters being used in urban areas will need more regular changing, often every 3 to 6 months. Basic filter maintenance is recommended between filter changes. This can be undertaken by cleaning gently or vacuuming the filters. We recommend that you read your manufacturer instructions for detailed cleaning instructions. Typically you should avoid using any liquids when cleaning. Our filters are "own brand" filters of FilterMate and are in no way approved by or associated with Nuaire or any of its affiliate companies and brands. The use of the Nuaire and system names and codes are solely used for the identification of which air filtration units the FilterMate own brand filters are intended to be used with.