How big is it really? Assembled it is roughly 18cm long with a bristle head of about 6cm - a standard full-size powder brush, not a mini.
Is it hard to pull apart? No. The joins are magnetic, not screw or friction fits, so sections separate and snap back in one motion.
Can I take it on a plane? Yes - makeup brushes are permitted in carry-on and checked luggage. Assembled, it's one piece rather than four.
Can I use it with liquid or cream products? It's designed for powder products. Liquids and creams are harder to clean out of the bristles and aren't recommended.
Is there anything to replace over time? No. All four pieces are bristle brushes - there is no sponge, pad or refill to buy.
What colours are available? Grey, Pink and Coffee handle finishes.