An inline fluid warming apparatus that has a fluid warmer portion and a battery portion for powering the fluid warmer portion. The fluid warmer portion has a housing that connects directly to a housing of the battery portion by an attachment means. The attachment can be a rail system or a snap attachment or any other secure means for attaching the two housings together. The fluid warmer portion has power contacts that engage with power contacts on the battery when the two portions are engaged. When the power contacts are engaged, the battery portion provides power to the fluid warmer portion to warm fluid traveling through the fluid warmer. The apparatus is placed directly onto an arm or leg of a patient. A band or adhesive may be used to hold the apparatus in place against the skin of the patient.
