Garmin B258 Bronze Thru-Hull Depth/Temp Transducer, 1kW, 50/200 kHz, 8-Pin

Overview

The Garmin 010-10703-20 is a B258 1 kW bronze thru-hull depth and temperature transducer with an 8-pin plug and a fairing block for hull deadrise up to 26 degrees. It operates at 50/200 kHz, uses a 39 ft cable, and has beamwidths of 14 x 23 degrees at 50 kHz and 3 x 5 degrees at 200 kHz. Maximum depth range is listed at 1,500 to 2,200 ft depending on conditions and frequency selection.

This is a traditional dual-frequency transducer meant for boats that want a thru-hull install for consistent readings and a clean bottom profile. The fairing block is there to correct the transducer angle on a V-hull so the face sits properly in the water when the boat is running.

Key features

• Traditional 1 kW 50/200 kHz sonar with depth and water temperature
• 8-pin transducer plug with a 39 ft cable
• Beamwidths: 14 x 23 degrees at 50 kHz and 3 x 5 degrees at 200 kHz
• Fairing block supports 0 to 26 degrees of deadrise for a proper through-hull aiming angle
• Thru-hull stem hole size is 30 mm (1-3/16 in.) with a usable shaft length of 121 mm (4.75 in.)
• Maximum depth range listed at 1,500 to 2,200 ft (conditions and installation affect results)

Compatibility and fit

This thru-hull bronze housing is intended for fiberglass or wood hulls. A bronze housing should not be installed in a metal hull, and it should not be used on a vessel with a positive ground electrical system.

Confirm the sounder connection before ordering. This model terminates in an 8-pin plug, and a separate adapter cable is needed if your Garmin sounder uses a 6-pin transducer port.

Installation and setup

A thru-hull install involves drilling a 30 mm (1-3/16 in.) hole, bedding the stem with marine sealant, and tightening the retaining nut to seal the hull. The fairing block is shaped to match your hull so the transducer face ends up aligned for accurate readings.

Choose a location where water flow stays smooth at speed, away from steps, strakes, intakes, and trailer bunks. Leave access inside the hull for tightening, cable routing, and periodic checks.

Secure the cable so it cannot chafe and avoid using the cable as a lifting point while positioning the transducer. The fairing block should be locked in place so it cannot rotate while underway.

Use cases on board

50 kHz is commonly used when you want coverage and depth reach, while 200 kHz tightens the beam for clearer bottom detail in shallower water. Switching between frequencies is a practical way to match conditions without changing hardware.

This transducer is a good match for offshore runs, deep-water fishing, and cruising boats that want depth and temperature from a thru-hull mount and have room for a fairing block under the hull.

Maintenance and care

Keep marine growth off the transducer face for consistent bottom tracking. After launch and during routine bilge checks, inspect the installation area for any signs of seepage.

Clean with methods that avoid harsh solvents on the transducer face and surrounding materials.

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Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

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Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

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Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

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