When you purchase one of the ER earphones, it comes with the default green filter and a removal tool. The same green filter and removal tool is included in this Tuning Kit along with new white, brown, red and orange filters.
Each of these filters modify the sound a bit and it was audible in my listening trials with the ER3XR earphones. I measured the filters using my IEC-711 compliant coupler and posted the graph above.
In general, for those who want more clarity and treble presence, the white and brown filters will add more there. The red filter reduces upper mids slightly and the orange filter adds a much warmer character to it by adding more bass and reducing the amount of upper mid-range and treble.
I tend to use the green and brown filters with my ER3XR, and I think the standard SR/SE series will have more use with these tuning filters than for owners with the XR sets. In this case, I can see the orange and red filters improving the SE/SR experience for me!