#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string& s) { return '"' + s + '"'; }
string to_string(const char* s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto& x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
void io() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
}
long long int inf = (long long int)LLONG_MIN;
void Solve() {
  int n;
  cin >> n;
  vector<long long int> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  vector<long long int> neg, pos;
  bool zero = false;
  for (int i = 0; i < n; ++i) {
    if (a[i] < 0) {
      neg.push_back(a[i]);
    } else {
      pos.push_back(a[i]);
    }
    if (a[i] == 0) zero = true;
  }
  sort(neg.begin(), neg.end(), greater<long long int>());
  sort(pos.begin(), pos.end());
  int sp = int((pos).size()), sn = int((neg).size());
  long long int ans = -inf;
  if (sn >= 2 && sp >= 3) {
    ans = max(ans, pos[sp - 1] * pos[sp - 2] * pos[sp - 3] * neg[sn - 1] *
                       neg[sn - 2]);
  }
  if (sn >= 4 && sp >= 1) {
    ans = max(ans, pos[sp - 1] * neg[sn - 4] * neg[sn - 3] * neg[sn - 1] *
                       neg[sn - 2]);
  }
  if (sp >= 5) {
    ans = max(ans, pos[sp - 1] * pos[sp - 2] * pos[sp - 3] * pos[sp - 4] *
                       pos[sp - 5]);
  }
  for (int i = 0; i < 5; ++i) {
    long long int crr = 1;
    if (sp >= i && sn >= 5 - i) {
      for (int j = 0; j < i; ++j) {
        crr *= pos[j];
      }
      for (int j = 0; j < 5 - i; ++j) {
        crr *= neg[j];
      }
      ans = max(ans, crr);
    }
  }
  if (ans < 0 && zero) {
    cout << 0;
    cout << "\n";
    ;
    return;
  }
  cout << ans;
  cout << "\n";
  ;
}
int main() {
  io();
  long long int t;
  cin >> t;
  for (int i = 0; i < t; ++i) {
    Solve();
  }
  return 0;
}
