According to the manufacturer's specifications, the systems weigh from 15 to 320 pounds (6.8 to 145.1 kg) and can emit sound in a 30Â- 60Â beam at 2.5 kHz.[54] They range in size from small, portable handheld units which can be strapped to a person's chest, to larger models which require a mount.[55] The power of the sound beam which LRADs produce is sufficient to penetrate vehicles and buildings while retaining a high degree of fidelity, so that verbal messages can be conveyed clearly in some situations.[56] Their weapons capability has been controversially used in the USA to disrupt numerous protests.[citation needed]

[Event "Reykjavik World Championship (16)"] [Site "Reykjavik"] [Date "1972.08.20"] [Round "16"] [White "Fischer, Robert James"] [Black "Spassky, Boris Vasilievich"] [Result "1/2-1/2"] [ECO "C69"] [WhiteElo "2785"] [BlackElo "2660"] [Annotator "Byrne,Robert"] [PlyCount "120"] [EventDate "1972.07.11"] [EventType "match"] [EventRounds "21"] [EventCountry "ISL"] [SourceTitle "MainBase"] [Source "ChessBase"] [SourceDate "1999.07.01"] 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 After all the violence of the previous game, Fischer is probably content to head for the tranquil channels of the Exchange Variation, the main theme of which is the exploitation of Black's doubled pawns in an endgame. dxc6 5. O-O The opening comes as no surprise to Spassky. (Almost a century ago, then World Champion Emanuel Lasker used to force the endgame immediately by 5. d4 exd4 6. Qxd4 Qxd4 7. Nxd4 In the last six years Fischer has preferred the Barendregt idea of castling first in order to give the plan potency by mobilizing a Rook.) 5... f6 6. d4 Bg4 7. dxe5 Qxd1 8. Rxd1 fxe5 9. Rd3 The Rook is somewhat awkwardly placed here, but White cannot work up any initiative as long as the King Knight remains pinned. Bd6 10. Nbd2 Nf6 11. Nc4 By this maneuver Fischer intends to exchange one of Black's strong Bishops, the chief feature of the defense. Nxe4 12. Ncxe5  Fischer improves on Bronstein's 12.Nfxe5, forcing Black to yield the Bishop pair at once without any repair of the doubled pawns. Bxf3 (Spassky Is unable to dispute the point by 12... Bf5 $2 since 13. g4 $1 Be6 14. Re3 Nf6 15. Ng5 leads to a decisive loss of material for Black.) 13. Nxf3 O-O 14. Be3 It looks now as though Fischer has everything that could be expected out of this type of opening. The White Kingside pawn majority is a clear advantage because the three pawns on the other wing are normally enough to blockade the Black pawn preponderance there, which are crippled by doubled pawns. And Fischer has eliminated the Queens and two sets of minor pieces, creating the simplified position in which such a structural superiority can be utilized. b5 $1 Striking back in an original and ingenious way, Spassky intends to throw the Queenside pawns forward, gaining space and putting on pressure to undouble the c-pawns. 15. c4 $2 Blocking with the c-pawn is the thematic way to counter such a plan, of course, but Spassky quickly proves it tactically unsound. (Best was 15. Nd2 for if Nxd2 (the retreat 15... Nf6 would permit a piece blockade with 16. Nb3 followed by either Nc5 or Bc5.) ( Spassky could have obtained considerable activity for his Bishop and Rooks by 15... Nc5 16. Bxc5 (not 16. Rc3) 16... Bxc5 17. Ne4 Bb6 18. Re1 Rae8 19. Kf1 and a fascinating struggle between dynamics and structure would have begun.) 16. Rxd2 c5 17. c4 would set up the blockade White wants.) 15... Rab8 $1  An unusual and strong continuation of the idea of his previous move by which White is saddled with the awkward task of finding a smooth defense for both the c and b-pawns. 16. Rc1 [#]Fischer's decision is to sacrifice a pawn, hoping to recover it later with positional advantage. (In any case, Black could not be denied effective counterplay, for if 16. b3 Ba3 (in order to answer 16... bxc4 by 17. Rd4 $1) 17. Rd7 (Perhaps 17. Rad1 is best: bxc4 18. bxc4 Bd6 19. Rb3 Rxb3 20. axb3 Rb8 21. Rd3 a5 22. g3 when the result will be a draw.) 17... bxc4 18. bxc4 Bd6 $1 19. Bd4 Nf6 20. Bxf6 Rxf6 and in the resulting position 21.c5 will free the Rook, but Black's strong Bishop gives him the endgame edge. Furthermore, the Black Rooks have such threats as R-e6-e7 and R-b4-a4 with great pressure.) 16... bxc4 17. Rd4 (If 17. Rxc4 Rxb2 and the Knight cannot be captured because of the threatening mate.) 17... Rfe8 18. Nd2 (18. Rc2 c3 $1 19. bxc3 Rb1+ 20. Bc1 Ng5 $1 21. Rd1 Nxf3+ 22. gxf3 gives Black the initiative and a clear advantage.) 18... Nxd2 19. Rxd2 Re4 20. g3 By removing backrank mate threats and preparing to bring his King strongly into play, Bobby ensures the draw. Be5 21. Rcc2 Kf7 22. Kg2 Rxb2 $1 23. Kf3 (The gain of a second pawn is only temporary. 23. Rxb2 is answered by c3) 23... c3 24. Kxe4 cxd2 25. Rxd2 Rb5 It is possible that White would be better after the exchange of Rooks, despite the pawn minus, because Black's extra pawn is doubled and weak. Spassky's move returns the pawn for a minute positional advantage. 26. Rc2 Bd6 27. Rxc6 Ra5 28. Bf4 $1  Fischer wisely sacrifices a pawn to bring about a standard drawn Rook-and-pawn ending, (because if 28. Rc2 Ke6 followed by ...Ra4+ would give White trouble.) 28... Ra4+ 29. Kf3 Ra3+ 30. Ke4 Rxa2 31. Bxd6 cxd6 32. Rxd6 Rxf2 33. Rxa6 Rxh2 34. Kf3 Now the game could have been given up as a draw, but since Fischer insists on playing everything out, Spassky decides to do the same today. Throughout the next 26 moves there was some tittering in the audience, which seemed amused at the spectacle of the two chess giants fooling around with an elementary position, like Frank Lloyd Wright playing in a sandbox. Rd2 35. Ra7+ Kf6 36. Ra6+ Ke7 37. Ra7+ Rd7 38. Ra2 Ke6 39. Kg2 Re7 40. Kh3 Kf6 41. Ra6+ Re6 42. Ra5 h6 43. Ra2 Kf5 44. Rf2+ Kg5 45. Rf7 g6 46. Rf4 h5 47. Rf3 Rf6 48. Ra3 Re6 49. Rf3 Re4 50. Ra3 Kh6 51. Ra6 Re5 52. Kh4 Re4+ 53. Kh3 Re7 54. Kh4 Re5 55. Rb6 Kg7 56. Rb4 Kh6 57. Rb6 Re1 58. Kh3 Rh1+ 59. Kg2 Ra1 60. Kh3 Ra4 1/2-1/2

Chess Fritz 13 Portable Hit