Mont. Code Ann. § 27-18-722

Before making such order, the court or judge must require an undertaking on behalf of the defendant, by at least two sureties, residents and freeholders or householders in the state, to the effect that in case the plaintiff recover judgment in the action, the defendant will, on demand, redeliver the attached property so released to the proper officer to be applied to the payment of the judgment or, in default thereof, that the defendant and sureties will, on demand, pay to the plaintiff the full value of the property released. The court or judge making the order may fix the sum for which the undertaking shall be executed, and if necessary in fixing such sum to know the value of the property released, the same may be appraised by one or more disinterested persons to be appointed for that purpose. The sureties may be required to justify before the court or judge, and the property attached cannot be released without their justification, if the same be required.