It sounds like you're looking at a microfiber fan duster that's both bendable and extendable, with a length of up to 100 inches. These types of dusters are quite handy for cleaning fans and other hard-to-reach places. Here are a few things you might want to consider:

Bendability: The ability to bend is great for reaching different angles and curves, especially around fan blades and vents.
Extendability: An extendable duster allows you to reach high or deep areas without needing a ladder, which is especially useful for ceiling fans and other overhead fixtures.
Microfiber Material: Microfiber is effective at trapping dust and allergens, and it’s generally washable, which means you can reuse it multiple times.
Length: At 100 inches (or about 8.3 feet), this duster should give you plenty of reach for most household tasks. Just be mindful of its weight and handling to ensure it’s comfortable to use.
Cleaning: Check if the duster head is removable and washable. Many microfiber dusters can be cleaned in the washing machine, but always follow the manufacturer's care instructions.
Storage: Consider where you’ll store the duster when it's not in use. Its extendable nature might make it a bit tricky to store in a small closet.