Mikasa Poker Shafts: Inner shaft is hard steel wires. This is strong in tensile and twisting stress and has resistance to wear. The outer hose is a robust structure with high torque resistant. Strong against high speed running, vibration and water. The outer liner on the outer hose prevents the inner shaft from premature damage by bending. Using a Poker Vibrator : Remove deep air pockets and voids in concrete walls with a Poker vibrator. Stand on the top of the wall forms, bracing one leg on either side as soon as possible after the wet concrete is poured into the forms. A Poker vibrator works only when the concrete is still very wet. Lower the Poker Vibrator needle into the middle of the wet concrete and turn on the power button. The weight of the Poker Vibrator needle, combined with the vibration, will allow it to sink quickly into the concrete. When the Poker Vibrator needle reaches the bottom of the form, pull it back up smoothly. Move approximately 1-foot down the wall and repeat the action. Each time the Poker Vibrator needle sinks into the wet concrete, it will help the concrete particles to settle into a solid mass and encourage trapped air to rise up and out of the wet concrete.