Great product, works are described. Take the time to check YouTube for video on how to prepare your filter. I didn't want to use cardboard as I wanted a stronger built. I used a hard plastic binder for parts and worked great.
ข้อดี: High quality product for sun watching. Produced great astrophotography of the sun and sun spots with this custom built filter.
ข้อเสีย: Explanation on how to built the filter are not so clear. Check YouTube for better explanations.