Furman AC-210A E Compact Power ConditionerSMP (Series Multi Stage Protection Plus) Furman SMP surge suppression virtually eliminates service calls. Traditional surge suppression circuits sacrifice themselves when exposed to multiple transient voltage spikes, requiring the dismantling of your system and repair of your surge suppressor. Not so with SMP. With Furman SMP, damaging transient voltages are safely absorbed, clamped, and dissipated no sacrificed parts, no service calls, no downtime.