TYPE 247-W WAVEMETER AND FILTER The range of the Type 247-W Wavemeter and Filter is 200 to 600 meters. Wavelengths arc determined by direct readings from the con denser dial, which is calibrated with an accuracy of within 2%. The filter coil may be connected either in series or parallel with the receiving set. When used in the series connection a single interfering broad cast station may be eliminated. The parallel filter is used to eliminate several interfering stations simultaneously and accept only one station within the filter range.  Free shipping in USA. Very clean inside.