Biffy Clyro have partnered with mental health charity CALM to release a T-shirt inspired by their 2008 single 'Mountains', with proceeds supporting suicide prevention services. The collaboration forms part of CALM's ongoing 'Lifelines' initiative, which invites musicians to design merchandise using lyrics or artwork meaningful to fans, harnessing artists' platforms to raise both funds and awareness for men's mental health in particular.

The all-black design features the lyric "I am a mountain. I am the sea" in red text and costs £30, with sales benefiting CALM's suicide prevention helpline and CALMzone app. Frontman Simon Neil said the song was about finding self-belief and confidence, urging fans to "stay strong, keep talking, and stay healthy", while CALM chief executive Simon Gunning praised the artists involved. Biffy Clyro join Blossoms, Tom Walker, Inhaler and Fontaines D.C. in supporting the charity, and the Scottish band have previously spoken candidly about mental health, including Neil's own struggles and UK suicide statistics showing it remains the leading cause of death for men under 45.