The U-Series is GE's latest design and it has a UniFit sample connector whichslides easily over the sample arm.The benefits of the U-Series nebulizer are:Resists blockage: The sample channel is uniform from the entry pointto the tip, so there is nowhere for particulates to be trapped.Fast washout: Since there is nowhere for sample to be trapped, thefastest possible washout and highest sample throughput is achieved.