Wow, look at this handyman dryer vent ducting! I can see two sizes of vinyl, solid metal, flexible metal and- for good measure- let’s couple it with ABS drain pipe. I’m not making this stuff up, I promise! This was discovered at recent home inspection in Oak Harbor on Whidbey Island. I always recommend installing solid metal ducting for safety reasons, and annually cleaning/maintaining as lint is flammable and can accumulate in dryer ducting.