The mattress should have straps that snap to the bunk door.
be sure to go over the bunk door area with a fine tooth comb.
many used hybrid buyers have found water intrusion issues later, because they weren't thorough enough.
Dan- Firefighter, Retired:C, Shawn- Musician/Entrepreneur:W, Zoe- Faithful Golden Retriever(RIP:(), 2014 Ford F150 3.5 EcoboostMax Tow pkg, 2016 PrimeTime TracerAIR 255 w/4pt Equalizer and 5 Mtn. bikes and 2 Road bikes