Inside mounted roller shades will have an approximate 1" vertical "light gap" between the edge of the fabric and the window casing on side with the cord loop, and a 5/8" light gap on the other side. This is because the fabric must be cut narrower than the operating mechanisms at the top. For room darkening applications consider adding side panels, an Outside Mount with 4 to 6" extra width or other room darkening products such as blackout honeycomb shades, which have smaller light gaps.
This product complies with CPSC child safety guidelines. If you have children in your home on a regular basis, CPSC recommends the use of cordless window coverings.