Kase magnetic square filter is an innovative mobile phone filter,which has abandoned traditional installation method of installing filter by clip.It uses a new magnetic installation method,enable you to install the square filter on the back of the phone or phone case by magnetic. Recommend use with a phone case: The magnetic piece adopts 3M adhesive.Before install,please clean the back of your phone or phone case,then press the magetic frame in the correct position place and let set for a few minutes,make sure that the magetic frame is sticked well.Then you can start to work. We recommend that you install the filter on a phone case,and replace your phone case when you use square filter to shoot. Kase Magnetic Square ND1000 Filter for Smartphone The square filter is made of HD optical glass,the size is 58x58mm(included the frame),much larger than ordinary mobile phone round filter,easily cover multiple lenses of most all smartphone without affecting the multiple lenses working at the same time. NOTICE:The size of the mobile phone lens group cannot be larger than 50x50mm. ND Filter Function ND Filter allows you to photograph with a longer shutter speed or wider aperture than normally required.The filter is often used torecord movement in subjects such as waterfalls,providing a silky smooth affect to flowing water. How to choose ND64 or ND1000? ND64 Filter provides a 6-stop exposure reduction,and ND1000 Filter provides a 10-stop exposure reduction.They are both used to extend the shutter time.The longer the shutter time is, the better the brushed atomization effect of flowing and moving objects will be. The ND1000 filter has outstanding brushed atomization effects when shooting lakes, waterfalls, clouds, seawater, etc. during the day. You can consider using the ND64 filter to shoot the sunset or the traffic flow at night. The use of ND filters is professional. If you are a beginner,when you use them, you continue to learn and accumulate shooting skills and experience. Isn’t it another fun?