Need some opinions here from the guys...

Getting my bro a bday gift for his 19th and he's blue thru-n-thru, so deciding between getting him a reusable Go Blue Wolverines stainless bottle (he's into every sport and always training, so thought it'd be more useful) http://www.brightandbold.com/greenbottleunivmichigan.html

OR

a sleeveless Mich tshirt I thought he could use for the weightroom: http://yahoosports.teamfanshop.com/NCAA_University_of_Michigan_T-Shirts/Michigan_Wolverines_Navy_Blue_Old_School_Football_Sleeveless_T-shirt

I need opinions since both would be useful, and he's already got a few Mich shirts, but you can never have too many, right? What would you rather get as a gift from your lil sis?