II.in [美 ɪn, 英 ɪn]副in often appears as the second element of certain verb structures in English (close in, hand in, stand in, etc). For translations, see the relevant verb entry (close, hand, stand, etc).
You see, the keyboards are actually a complementary colour (silver on the white model, black on the green, etc.) with a removable rubber cover in the primary colour.