n=int(input())
for i in range(n):
z=int(input())
wartosci=input().split()
for j in range(z):
wartosci[j]=int(wartosci[j])
wartosci.sort()
print(max(wartosci[z-1]*wartosci[z-2]*wartosci[z-3],wartosci[z-1]*wartosci[0]*wartosci[1]))
bj1pbnQoaW5wdXQoKSkKZm9yIGkgaW4gcmFuZ2Uobik6Cgl6PWludChpbnB1dCgpKQoJd2FydG9zY2k9aW5wdXQoKS5zcGxpdCgpCglmb3IgaiBpbiByYW5nZSh6KToKCQl3YXJ0b3NjaVtqXT1pbnQod2FydG9zY2lbal0pCgl3YXJ0b3NjaS5zb3J0KCkKCXByaW50KG1heCh3YXJ0b3NjaVt6LTFdKndhcnRvc2NpW3otMl0qd2FydG9zY2lbei0zXSx3YXJ0b3NjaVt6LTFdKndhcnRvc2NpWzBdKndhcnRvc2NpWzFdKSk=