This a professional underground metal detector with LCD,It has three tones to indicate different metals

It is a good choice for main order company MD-3020II hobby metal detector:

• Three operation modes: all metal, disc, notch
• LCD displays the type and depth of the target
• Sensitivity: >15cm (for the US quarter)
• Low battery indication
• Three tones to indicate different types of metal
• Frequency: approx 6.6kHz
• Variable S-rod shaft length and arm support handle for convenient and comfortable use
• 8" waterproof search coil
• Two 9V batteries required

Gold range

• Iron foil: indicates that the target is probably iron or foil, some oxidized iron might register somewhere within the silver range
• 5¢ (nickel): indicates that the target is probably 5¢ or a nickel, some small gold rings might register within this range
• Pull tab: indicates that the target is probably a pull tab of an aluminum can, some small gold rings might register within this range, might register within pull tab category
• S-caps: indicates that the target is probably a type of metal like bottle cap with whorl, some medium sized gold rings might register within this category
• 1¢: indicates that the target might be a zinc penny or a copper coin, some large rough gold items might register within 1¢ category

Silver range:
1¢ 25¢, indicates that the target is probably silver coin, 25¢ or 1¢
Some large aluminum coin might register within 1¢ 25¢ category 

This a professional underground metal detector with LCD
It has three tones to indicate different metals
It is a good choice for main order company
MD-3020II hobby metal detector:

• Three operation modes: all metal, disc, notch
• LCD displays the type and depth of the target
• Sensitivity: >15cm (for the US quarter)
• Low battery indication
• Three tones to indicate different types of metal
• Frequency: approx 6.6kHz
• Variable S-rod shaft length and arm support handle for convenient and comfortable use
• 8" waterproof search coil
• Two 9V batteries required

Gold range

• Iron foil: indicates that the target is probably iron or foil, some oxidized iron might register somewhere within the silver range
• 5¢ (nickel): indicates that the target is probably 5¢ or a nickel, some small gold rings might register within this range
• Pull tab: indicates that the target is probably a pull tab of an aluminum can, some small gold rings might register within this range, might register within pull tab category
• S-caps: indicates that the target is probably a type of metal like bottle cap with whorl, some medium sized gold rings might register within this category
• 1¢: indicates that the target might be a zinc penny or a copper coin, some large rough gold items might register within 1¢ category

Silver range:
1¢ 25¢, indicates that the target is probably silver coin, 25¢ or 1¢
Some large aluminum coin might register within 1¢ 25¢ category 

Feature : 

LCD Display —shows the probable type of metal with an arrow, the depth of the target, DISC/NOTCH range, 

the level of SENS with segment, the operating mode, and low battery indication.

Three Tone Audio Discrimination — sounds distinctive tones for different types of metal.

Notch — ignores junk metal and finds valuable items by setting the disc and notch range.

Super Slow Sweep Identification — with a very slow sweep of the search coil to discriminate different types of metals.

Headphone Jack — lets you connect headphones (not supplied) and operate without trouble.

Waterproof Search coil — lets you use the detector even if you must put it under water.