All our hospital beds come with two side rails

The full automatic package comes with two half rails (better to use as grips to get in and out of bed)

or full length side rails. (Better at preventing someone from falling out of bed when caregivers are not around to help)

Either type of side rail drops down below the surface of the mattress if needed or stays in the upright position via a spring loaded pin.
 

If at a later date your needs change a brand new set of side rails is available for $229-$279. They are usually in stock and can be picked up any day of the week.