S.C. Code § 15-19-310
Upon application for an order to discharge the attachment, the defendant shall deliver to the court or officer an undertaking executed by at least two sureties who are residents and freeholders or householders in the State, approved by such court or officer, to the effect that such sureties will, on demand, pay to the plaintiff the amount of judgment that may be recovered against the defendant in the action, not exceeding the sum specified in the undertaking which shall be at least double the amount claimed by the plaintiff in his complaint. If it shall appear by affidavit that the property attached be less than the amount claimed by the plaintiff the court or officer issuing the attachment may order the property to be appraised and the amount of the undertaking shall then be double the amount so appraised.
S.C. Code § 15-19-310