TC 5WIRE WHIP W/ L21-20 55FT InfraStruXure Whips deliver power from APC's InfraStruXure Power Distribution Units to rack loads in modern data center environments. Use InfraStruXure Whips to power up single- or three-phase loads. InfraStruXure Whips can connect from the InfraStruXure Power Distribution Units directly to your server or to a second rack-based Power Distribution Units for the purpose of powering hubs and other rack equipment.