Mr Brog Briar Wood Block Pre Drilled Ready to Smoke Tobacco Pipe - Carve Your Own Outer Shape Design for The Perfect Pipe

What type of briar is it? where does the briar originate from? thank you

is the stem vulcanite or acrylic?

will this hold a 9mm filter?

When working these blocks do you find voids and/or sand pits in the briar? Or is it good briar without those imperfections? I see bondo in the pic.