LH521 is a high quality battery from Lucas. The cold cranking current of the battery is 390 A. The dimensions of the product are 291 x 173 x 221 mm. You should use the dimensions of your old battery as a guide for your selection. Durable Wet technology for your vehicle The LH521 has a capacity of 117 Ah. The higher the value, the more electrical charge can be stored in the battery. Wet batteries like the LH521 are suitable for vintage marine applications with standard energy needs. They offer reliable performance for marine use. The technology of this battery supports power requirements in vintage marine environments. You should consider this when buying Before you buy, check that the circuit and polarity of your new battery are identical to the values of the old model. The circuit shows whether the positive pole is on the right or left of the battery. To determine this, position the battery so that the poles are facing you. With the LH521, the circuit is 0, so the positive pole is on the right.