Hi, I was talking to a Rednose person at the baby expo and they cautioned to be careful of buying mattresses with a mattress topper. I was think of buying this one, but noticed it has a 10mm latex and foam topper. Is it safe? And if not, can you recommend an alternative for a similar price or less? https://tasmaneco.com.au/product/orthopaedic-pocket-spring-cot-mattress/?sku=T-313

Red Nose recommends the following when buying a mattress for a cot.
A safe mattress is one that is the right size for the cot, is firm, clean and in good condition and is placed flat (not tilted or elevated).

Right size: Ensure the mattress complies with the size and depth recommended by the manufacturer of the cot. A baby or toddler can get stuck in gaps between a poor fitting mattress and the cot sides. This is especially dangerous if their face is trapped and covered, or their neck is restricted in any way. Make sure there is no more than a 20mm gap between the mattress and the cot sides and ends

Firm: Use a firm sleep surface that is compliant with the new AS/NZS Voluntary Standard (AS/NZS 8811.1:2013

https://rednose.org.au/article/what-is-a-safe-mattress

If there is anything that is added to the surface of the mattress, ensure it doesn’t “take away from” the firmnesss of the mattress.
eg - this may occur with some mattress toppers/lambswool/mattress protectors

Always look for product information when buying any product for baby.
I noticed this information when looking at the link you mentioned above.

Product Details
This mattress has been tested and approved in line with Australian Cot Mattress Standards, AS/NZS 8811.1:2013.
https://tasmaneco.com.au/product/orthopaedic-pocket-spring-cot-mattress/?sku=T-313#popup2