Overview Product Description Replacement gas ballast knob for the LACO W2V10, W2V20, W2V40 and W2V80. Product Videos Product Reviews Write a Review Write a Review × Gas Ballast Knob (W2V10, W2V20, W2V40, W2V80) Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *