Lighthouse SF Mounts – 217 X 148d mm, Pack of 6, Black. Large “”D”” mounts are closed at top and bottom, but open at back. Small “”d”” mounts are double sealed, closed top and bottom. Optimal protection against dust, moisture, colour changes and sticking. Strong seam securely holds stamp in place. Free from all harmful chemical agents. Special adhesive provides safe and solid bond with album pages.