The Force Multiples module allows you to require that certain products can only be purchased in certain increments. For instance, you may have a widget XYZ123 that is sold in packs of 4. Force Multiples can be used to require customers to purchase XYZ123 in multiples of 4 (4, 8, 12, etc). Any or all products in the store can be required to have multiples. Products not flagged as requiring multiples are not affected by the module.

Checks are performed when products are added to the basket, or when the quantity in the basket is changed. By default the error message, which tells the customer that they are attempting to add an invalid quantity, can appear on the product, category, basket, and search screens. The error message text and formatting is completely customizable.

Store Morph Technology (SMT) entities are provided for the error message and for the multiple required for each product.