Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Colt model no. | Name | Stock | Fire control | Rear sight | Forward assist | Barrel length | Barrel profile | Barrel twist | Hand guards | Bayonet Lug | Muzzle device |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| LE1020 | Gas Piston Carbine | 4th Generation | S-1 | Flattop | Yes | 16 in. | M4 | 1:7 | Rail System | Yes | A2 |
| LE1033 | Gas Piston Commando | 4th Generation | S-1 | Flattop | Yes | 11.5 in. | A2 | 1:7 | Rail System | Yes | A2 |
| LE6920HB | Law Enforcement Carbine | 4th Generation | S-1 | Flattop | Yes | 16 in. | M4 HBAR | 1:7 | M4 | Yes | A2 |
| LE6921 | M4LE Carbine | 4th Generation | S-1 | Flattop | Yes | 14.5 in. | M4 | 1:7 | M4 | Yes | A2 |
| LE6921CQB | M4LE Carbine | 4th Generation | S-1 | Flattop | Yes | 10.5 in. | M4 HBAR | 1:7 | M4 | Yes | A2 |
| LE6921HB | M4LE Carbine | 4th Generation | S-1 | Flattop | Yes | 14.5 in. | M4 HBAR | 1:7 | M4 | Yes | A2 |
| LE6921SP | M4LE Carbine | 4th Generation | S-1 | Flattop | Yes | 10 in. | M4 HBAR | 1:7 | M4 | Yes | A2 |
| LE6933 | M4LE Commando | 4th Generation | S-1 | Flattop | Yes | 11.5 in. | A2 | 1:7 | Short Ribbed | Yes | A2 |
Question:
What hand guard system is used with a gas piston commando?
Answer:
Rail System