The TMA-3 is a circular Yugoslavian minimum metal anti-tank blast mine.
 It is very similar in appearance to the TMA-4.
 The mine consists of a cast circular block of explosive cased in resin reinforced fabric.
 The top of the mine has three fuze wells which each take a UTMA-3 fuze, and a fourth secondary fuze well is provided in the base of the mine to fit an anti-handling device.
 The fuze wells may also accept a number of other fuzes, including the UPROM-1, and other fuzes, potentially allowing tripwire activation.
 The small pressure plate area of the UTMA-3 fuzes gives the mine good resistance to minefield clearance techniques which used blast overpressure techniques i.e. explosive charges.
A pyrotechnic fastener (also called an explosive bolt, or pyro, within context) is a fastener, usually a nut or bolt, that incorporates a pyrotechnic charge that can be initiated remotely.
 One or more explosive charges embedded within the bolt are typically activated by an electric current, and the charge breaks the bolt into two or more pieces.
 The bolt is typically scored around its circumference at the point(s) where the severance should occur.
 Such bolts are often used in space applications to ensure separation between rocket stages, because they are lighter and much more reliable than mechanical latches.
A Bangalore torpedo is an explosive charge placed within one or several connected tubes.
 It is used by combat engineers to clear obstacles that would otherwise require them to approach directly, possibly under fire.
 It is sometimes colloquially referred to as a "Bangalore mine", "banger" or simply "Bangalore".
A depth charge is an anti-submarine warfare weapon.
 It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock.
 Most depth charges use high explosive charges and a fuze set to detonate the charge, typically at a specific depth.
 Depth charges can be dropped by ships, patrol aircraft, and helicopters.
A mine-clearing line charge (abbreviated MICLIC and pronounced or ""mick-lick"") is used to create a breach in minefields under combat conditions.
 While there are many types, the basic design is for many explosive charges connected on a line to be projected onto the minefield.
 The charges explode, detonating any buried mines, thus clearing a path for infantry to cross.
 The system may either be human-portable or vehicle-mounted.
 The systems do not guarantee clearance of all types of mines.
Erythritol tetranitrate (ETN) is an explosive compound chemically similar to PETN.
 It is however thought to be 1/3 more sensitive to friction and impact.
 ETN is not well known, but in recent years has been used by amateur experimenters to replace PETN in improvised detonation cord or in boosters to initiate larger, less sensitive explosive charges.
 Due to the availability of erythritol as a natural sweetener and its relative ease of production in relation to PETN, ETN is a favoured homemade explosive compound to the amateur experimenter.
An explosive lens—as used, for example, in nuclear weapons—is a highly specialized shaped charge.
 In general, it is a device composed of several explosive charges.
 These charges are arranged and formed with the intent to control the shape of the detonation wave passing through them.
 The explosive lens is conceptually similar to an optical lens, which focuses light waves.
 The charges that make up the explosive lens are chosen to have different rates of detonation.
 In order to convert a spherically expanding wavefront into a spherically converging one using only a single boundary between the constituent explosives, the boundary shape must be a paraboloid; similarly, to convert a spherically diverging front into a flat one, the boundary shape must be a hyperboloid, and so on.
 Several boundaries can be used to reduce aberrations (deviations from intended shape) of the final wavefront.
The Battle of Bardia was fought over three days between 3 and 5 January 1941, as part of Operation Compass, the first military operation of the Western Desert Campaign of the Second World War.
 It was the first battle of the war in which an Australian Army formation took part, the first to be commanded by an Australian general and the first to be planned by an Australian staff.
 Major General Iven Mackay's 6th Division assaulted the strongly held Italian fortress of Bardia, Libya, assisted by air support and naval gunfire, and under the cover of an artillery barrage.
 The 16th Infantry Brigade attacked at dawn from the west, where the defences were known to be weak.
 Sappers blew gaps in the barbed wire with Bangalore torpedoes and filled in and broke down the sides of the anti-tank ditch with picks and shovels.
 This allowed the infantry and 23 Matilda II tanks of the 7th Royal Tank Regiment to enter the fortress and capture all their objectives, along with 8,000 prisoners.
The mines in the Battle of Messines comprised a series of underground explosive charges, secretly planted by British tunnelling units beneath the German 4th Army lines near the village of Mesen ("Messines" in French, historically used in English) in Belgian West Flanders during the First World War.
 The mines were detonated at the start of the Battle of Messines (7–14 June 1917) , creating 19 large craters.
 The joint explosion of the mines at Messines ranks among the largest non-nuclear explosions of all time.
 The evening before the attack, General Sir Charles Harington, Chief of Staff of the Second Army (General Sir Herbert Plumer), remarked to the press, "Gentlemen, we may not make history tomorrow, but we shall certainly change the geography".
 The Battle of Messines marked the zenith of mine warfare.
 On 10 August 1917, the Royal Engineers fired the last British deep mine of the war, at Givenchy-en-Gohelle near Arras.
Detonating cord (also called detonation cord, detacord, det. cord, detcord, primer cord or sun cord) is a thin, flexible plastic tube usually filled with pentaerythritol tetranitrate (PETN, pentrite).
 With the PETN exploding at a rate of approximately 6400 m/s, any common length of detonation cord appears to explode instantaneously.
 It is a high-speed fuse which explodes, rather than burns, and is suitable for detonating high explosives.
 The velocity of detonation is sufficient to use it for synchronising multiple charges to detonate almost simultaneously even if the charges are placed at different distances from the point of initiation.
 It is used to reliably and inexpensively chain together multiple explosive charges.
 Typical uses include mining, drilling, demolitions, and warfare.

Question: The Battle of Bardia included explosive charges that are placed in what kind of connected housings?
Answer: tubes