import sys
from math import *
for _ in range(int(input())):
n = int(input());
a = list(map(int,input().split()));
a.sort();
ans = -10**18;
for i in range(n):
ans = max(ans, a[i%n]*a[(i+1)%n]*a[(i+2)%n]*a[(i+3)%n]*a[(i+4)%n]);
print(ans);
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
int main() {
int t;
cin>>t;
while(t--){
ll n;
cin>>n;
ll ar[n];
for(ll i=0;i<n;i++){
cin>>ar[i];
}
sort(ar,ar+n);
ll m1=ar[0]*ar[1]*ar[2]*ar[3]*ar[4];
ll m2=ar[n-1]*ar[n-2]*ar[n-3]*ar[n-4]*ar[n-5];
ll ans=max(m1,m2);
ll m3=ar[0]*ar[1]*ar[2]*ar[3]*ar[n-1];
ll m4=ar[0]*ar[1]*ar[n-3]*ar[n-1]*ar[n-2];
ll ans1=max(m3,m4);
ans=max(ans,ans1);
cout<<ans<<"\n";
}
return 0;
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