Look to buy possible retest of support at 1646 or close to it with tight stop under Wednesday's low. On US open if price is above the 4pm close and gaps up, watch for the gap to possibly fill and find support there @1657. Next levels of support 1626 & 1600/1596 zone that was a strong level of support that helped launched July's rally. Alt - sell on signs of resistance at 1667 to 1674 or upper channel. If upper channel is broken, watch for signs of resistance at 1692/93 to sell.