I'm looking at storing a data type with 7 fields in an unboxed vector, which means that I'll have to use GenUnboxTuple to create an instance for Unbox (a,b,c,d,e,f,g), but I was thinking that another solution is to use "instance (Unbox a, Unbox b) => Unbox (a,b)" recursively to create "instance Unbox (a,(b,(c,(d,(e,(f,g))))))". Is there any reason I shouldn't say something like, import qualified Data.Vector.Unboxed as Vector data X = X Int Int Int Int Int Int Int toTuple (X a b c d e f g) = (a,(b,(c,(d,(e,(f,g)))))) toVector = Vector.fromList . map toTuple I guess I'm wondering if there is a technical reason why I should use an explicit Unbox instance for 7-tuples, or if it's just a convenience to have Unbox defined for tuples > 2? Thanks, Jeff