421 is a high quality battery from Numax. The cold cranking current of the battery is 270 A. The dimensions of the product are 174 x 169 x 218 mm. You should use the dimensions of your old battery as a guide for your selection. Durable Wet technology for your vehicle The 421 has a capacity of 58 Ah. The higher the value, the more electrical charge can be stored in the battery. Wet batteries like the 421 are suitable for marine applications with starting needs. They offer reliable performance for heavy duty marine use. The technology of this battery supports starting and power requirements in 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 421, the circuit is 0, so the positive pole is on the right.