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The ornamental design for a ph testing device, as shown. |
FIG. 1 is a plan view of the pH testing device showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a side elevational view thereof;
FIG. 5 is an elevational view showing the opposite side;
FIG. 6 is a bottom view thereof.
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D275268, | Jul 10 1981 | Fisons Limited | pH Meter, or the like |
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Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Aug 02 1976 | J & M Instruments Corp. | (assignment on the face of the patent) | / |
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