Specs are quantitative aspects of the option such as the price
Pros
Pro
Great for reproducing your baby's experience inside the womb
This is the only sound machine with that a heartbeat track. Many babies get comfort out of the heartbeat sound on loop since it makes them feel like they're inside the womb again.
It's lightweight and portable to stash in your diaper bag. Having a battery operated option gives you flexibility to travel without worrying if there will be a conveniently placed outlet or not.
A set of new AAA batteries would only take 2-3 days to get consumed. While this may be an affordable product, you will spend a lot of money on replacement batteries so it is advisable to use rechargable ones.