The special unitary group SU(n) has the stable homotopy type of a wedg
e of n - 1 finite complexes. The 'first' of these complexes is Sigma C
Pn-1, which is well known to be indecomposable at the prime 2 whether
n is finite or infinite. We show that the 'second' finite complex is a
gain indecomposable at the prime 2 when ii is finite, but splits into
a wedge of two pieces when n is infinite.