yes, on both sides of the filter 

Built in. Only need sun or plug in charger ( it comes with one) to power up. 

Depends on what you mean by direct sunlight. If you mean the filter pointed directly at the sun, and you are worried about lens flare, well it wont stop that. But if you mean using it out in bright bright sunlight all around, then it works great. I'm a member of the Longview Film Club. We shoot indie short films, and use these for all of lenses and cameras. It's a must when shooting outside under almost any conditions. Makes it possible to get nice Depth of Field even on a sunny day. 

hello ,you can use ie take picture of the sun, but not for the solar eclipse 

1. Please lock tight on the twist lock and check there is no any issue on tube locking ring and tube sand proof hat
2. Keep the center axis perpendicular to the ground
3. Column Hook allows you to hang additional weight to increase stability
4. For camera with telephoto zoom lens, we recommend you buy a tripod mount ring for better balance