Developed by GEC Marconi, originally for the Batch 2 Leander Class frigates. A very low frequency, passive, 500m long towed array, it underwent trials, initially on HMS Matapan, then on HMS Lowestoft (a Type 12 Rothesay Class frigate) around 1977/78. First conversions to Leander Class began in 1980. 
Used by |
| 1983 |  Type 22 (Batch 2) Boxer class frigate FF | 1 |
| 1983 | Towed Array Exocet Leander class frigate FF | 1 |
| 1988 | Type 22 (Batch 3) Cornwall class frigate FF | 1 |
| 1989 | Type 23 Duke class frigate FF | 1 |
Refits |
| 1971 | HMS Matapan D43 | Destroyer Later Battle class | towed to Portsmouth and converted by 1973 into a sonar trials ship and fitted with a flight deck |
| 1976-oct-11 | HMS Lowestoft F103 | Frigate Type 12 Rothesay class | until Sep 1977 at HMD Portsmouth to re-equip as Trials and Training Ship. Lowestoft distinguished herself with trials of the Type 2031 sonar. |
| 1981-feb | HMS Phoebe F42 | Frigate Towed Array Exocet Leander class | upgrade to towed array sonar, completed 1982 |
| 1982-jan | HMS Cleopatra F28 | Frigate Towed Array Exocet Leander class | new sonar array fitted by Apr 1983 |
| 1982-aug | HMS Argonaut F56 | Frigate Towed Array Exocet Leander class | new sonar array fitted by Nov 1983 |
| 1983 | HMS Naiad F39 | Frigate Ikara Leander class | fitted with new sonar array, by 1984 |
| 1985-apr | HMS Sirius F40 | Frigate Towed Array Exocet Leander class | new sonar array fitted by Nov 1985 |
In Service |
 Chilean Navy |
| Royal Navy |
