A chinchilla does not wash in water. It washes by rolling, and the sand is doing a job that a bath would do for another animal — which is why Selective describe a sand bath as a way of letting a pet express a natural instinct rather than as a grooming product.

What makes a bathing sand good is uniformity. Selective's particles are all a very similar size, which is what makes it feel soft rather than gritty and is why they say it suits pets with very sensitive skin. Their own method is to put about 2.5cm of it into a high-sided tray and let the animal bathe for up to 10-20 minutes at a time, taking out any soiled sand straight away and changing the lot at least once a week. The pack is 1KG and reseals to keep moisture out.

• 1KG resealable pack
• Particles all a very similar size
• Selective's method: about 2.5cm in a high-sided tray
• Bathing sessions of 10-20 minutes at a time
• Change the sand at least once a week
• Suitable for pets with very sensitive skin

On the housekeeping. Selective's own instruction is to change the sand at least weekly and lift out anything soiled straight away, so 1KG is a consumable rather than a purchase — work out how often you will be buying it before you decide it is cheap. There is also no composition on anything supplied to us: nothing says whether this is a washed natural sand or a manufactured dust, which is the one thing a keeper worried about respiratory irritation would want to know.

Who it's for: chinchilla keepers, who need this daily, and owners of degus, gerbils or hamsters, who Selective say enjoy a bath every few days as a treat.